What are sleep disorders? |

Causes and Symptoms

Sleep is more than the absence of wakefulness. While a person sleeps, the brain continues to be quite active—indeed, this activity is essential for human survival. Brain activity can be measured in sleeping subjects and has been used to classify sleep into stages 1 through 4, where stage 1 is the lightest sleep and stage 4 is the deepest. A sleeper moves from stage 1, through stages 2 and 3, and to stage 4, and then back through stages 2 and 3 to stage 1. This cycle occurs every ninety to one hundred minutes throughout the night. During the latter part of the sleep period, stage 1 sleep is associated with brain activity that is as intense as that seen in waking subjects. During these periods of intense brain activity, rapid eye movements (REMs) are observed, and as a result these periods are referred to as REM sleep, and the other sleep stages are referred to as non-REM sleep. Although the precise function of sleep is still hotly debated in scientific circles, most people can verify from experience that adequate sleep has a major impact on their ability to function effectively and on their emotional stability. For those who suffer from a sleep disorder, life can become a daily struggle; sleep disorders often
have severe physical, financial, and social consequences.

Patients who are having difficulty with sleeping usually complain of insomnia, feeling sleepy during the day, or abnormal behaviors during sleep. Sleep disorders have been divided into four broad categories by the Association of Sleep Disorders Centers: the insomnias, or disorders of initiating or maintaining sleep; the hypersomnias, or disorders of excessive sleep; disorders of the sleep-wake cycle; and the parasomnias, or disorders of partial arousal such as sleepwalking and night terrors. Of these, the most common complaint are the insomnias.

Insomnia is a subjective complaint of nonrefreshing sleep. Patients believe that their ability to function during the day is impeded by short or poor-quality sleep. Since most people experience transient insomnia at various times in their lives, chronic insomnia is defined as insomnia lasting longer than three months. Individuals with insomnia have a variety of sleep patterns: Some may require a long period to fall asleep, some wake up after a few hours and cannot fall asleep again, and some may not know that they have awakened briefly hundreds of times during the night. The sleep patterns of the insomniac can vary from night to night, which increases the anxiety of the patient. Electrical monitoring of brain activity shows that most insomniacs have only a slightly reduced total sleep time, with few changes in sleep stages. Physiologically, poor sleepers have been shown to maintain a higher body temperature during sleep than normal sleepers, which may reflect a higher level of arousal. Insomnia is not a necessarily disorder in itself; instead, it can be a symptom of a large number of underlying disorders. These can be physiological, psychological, or behavioral in nature, or they can be a normal part of the aging process.

Insomnia can be caused by medical problems that interfere with breathing, such as sleep apnea, in which patients have multiple episodes each night when they stop breathing. A single episode can last ten seconds to two minutes, and in some severe cases, up to 50 percent of sleep time can be spent without breathing. Sleep
apnea is often seen in obese men and women because of obstruction of the air passage. Clinical signs include irregular snoring and daytime sleepiness. Insomnia can also be caused by neurological problems, muscular problems, or conditions that cause pain. Periodic leg movement can (but does not always) cause multiple awakenings during the night, as can a related disorder called restless leg syndrome, which is characterized by a creeping sensation in the legs. Psychiatric research has demonstrated that insomnia can be a symptom of clinical depression. Surveys have shown that insomniacs have a higher level of stress, tension, and anxiety than normal sleepers. In addition, insomnia can occur when behavioral patterns do not encourage sleep. The use of
caffeine or engaging in arousing activities just prior to bedtime can contribute to poor sleep. The normal aging process usually causes a decrease in total sleep time, in stage 1 sleep, and an increase in fragmented sleep, resulting in drowsiness and sometimes depression in the elderly.

In addition to all these causes, there are some individuals who complain of insomnia in which no abnormalities can be found. When comparing subjective reports from the patient to sleep recordings in the laboratory, there is a tendency for such insomniacs to report wakefulness even though the sleep recording indicates that the patient is sleeping normally. It appears that there are other sleep abnormalities that contribute to the quality of sleep which remain unknown.

The hypersomnias are defined by excessive daytime sleepiness (EDS) and include the group of patients who are unable to stay awake during the day. Several external circumstances can contribute to EDS, such as jet lag, shift work, medications, or some of the disorders underlying insomnia listed above. In addition,
narcolepsy, a central nervous system disorder, is characterized by the overwhelming need to sleep several times a day. These sleep attacks often occur without warning. Narcoleptics can also experience cataplexy, or sudden muscle weakness when in emotionally charged situations that cause anger, laughter, or fear. They may also experience hallucinations when sleep begins or
sleep paralysis upon waking that can last for several minutes. Narcolepsy affects 0.05 percent of the population and causes significant hardship to those afflicted. It
can pose a danger if the person falls asleep while operating a car or when in a dangerous environment.

The daily cycle of wakefulness followed by a prolonged sleep period is controlled by circadian rhythms. People who travel across time zones or who work rotating shifts are often forced to sleep at a time when their circadian rhythm supports wakefulness and work when their circadian rhythm supports sleep. Other individuals have defects in the mechanisms that regulate circadian rhythms and may experience delayed or advanced sleep phase syndrome in which there is a shift of the normal twenty-four-hour cycle. If they follow their circadian rhythm, these patients will sleep for a normal amount of time; however, the social consequences of retiring at 7:00 p.m. or awakening at noon are prohibitive. Internal desynchronization between the sleep-wake cycle and the closely related circadian temperature cycle can also contribute to poor-quality sleep.

The parasomnias, or disorders of arousal, include sleepwalking and night terrors. Both of these disorders occur predominantly in childhood, although they can be experienced by adults. When brain activity is characterized by an electroencephalograph (EEG), there are elements of both wakefulness and REM sleep, often in the deepest stages (3 and 4). This finding dispels the myth that sleepwalkers are acting out dreams, since dreaming occurs during REM sleep. Sleepwalking activity can vary in length. The person usually has his or her eyes open, can respond verbally, and can move about normally. Sleepwalkers are usually aware of the environment at some level, although their judgment is impaired and they can sometimes injure themselves. Night terrors involve signs of panic such as shrieking, sweats, and frenzied movements and can be distinguished from nightmares, which involve little movement and more extensive memory. Both sleepwalking and night terrors are usually not recalled, and there is little connection between these syndromes and psychiatric disease. Both may be exacerbated by sleep deprivation, stress, fever, or medications.

Treatment and Therapy

One of the difficulties in diagnosing insomnia or one of the other sleep disorders is that there is much individual variability among normal sleepers in sleep needs and amount of sleep logged each night. Therefore, what may be adequate sleep for one person might cause another to report poor sleep. To determine the causes of poor sleep, a person is usually referred to a sleep clinic. There, a detailed history of the problem as well as a description of the patient’s sleep habits, lifestyle, and psychological state is recorded. Often, a description of behavior during sleep from someone who shares the bedroom can provide additional important information. Next, a polysomnogram, in which the sleeping patient is monitored with electrodes, is performed so that information on brain waves, breathing, muscle movements, and blood oxygen levels can be obtained. Sometimes this test is administered in the sleep center, and sometimes it is done in the more natural sleep environment of the person’s home using ambulatory monitoring devices. From this information, a diagnosis usually can be made and the appropriate therapy determined.

When insomnia is associated with an underlying psychiatric or medical problem, treatment usually begins with the primary problem rather than with the symptom of poor sleep. When the primary problem is solved, the sleep pattern usually returns to normal. Symptomatic treatment of the insomnia itself is provided only when the cause of the sleep disturbance cannot be treated. There are two major approaches: treatments that emphasize the use of drugs or technical aids and treatments that emphasize a change in behavior.

Although over-the-counter aids cannot improve sleep, large numbers of prescription drugs can affect sleep patterns and influence alertness during waking hours. Historically, barbiturates were administered for insomnia, but in 1970, benzodiazepines were introduced; they are now the most commonly prescribed drugs for sleeplessness. These drugs are usually taken about thirty minutes before bedtime, causing drowsiness and thus decreasing the amount of time it takes to fall asleep. Benzodiazepines alter the stages of sleep, decreasing the amount of stage 1 and REM sleep and increasing the amount of stage 2 sleep. The significance of these changes is not understood. When used alone, benzodiazepines are very safe and have few side effects; if they are combined with other drugs, however, there can be a toxic interaction. Although most people can tolerate these drugs and report no daytime grogginess, some impairment of function may exist upon waking. There is strong evidence to suggest that benzodiazepines be used for only a short period of time. With continued use (longer than thirty days), patients usually find that the drug
becomes less effective unless the dosage is increased to an unsafe level. When the drug is discontinued, the original symptoms of insomnia usually recur and often a “rebound insomnia,” which is even more severe than before the drug treatment began, may be present for a brief period. Because of these limitations, these “sleeping pills” are usually given when an acute but temporary situation exists. To treat insomnia that is caused by periodic leg movements, a muscle relaxant is sometimes used. For patients whose sleep apnea is not resolved by weight reduction, mechanical devices that hold the air passage open during sleep are usually employed. Orthodontic aids or tongue retainers may provide relief, and other patients wear masks that hold the air passage open, providing a continuous airflow during sleep.

Since insomnia is often caused by poor habits that condition the sleeper to remain awake, the problem can sometimes be solved by a simple commitment to avoid naps, reduce caffeine and alcohol intake, eat light meals in the evening, reduce noise in the sleep environment, and establish a regular bedtime. Many insomniacs are so preoccupied with the fear that they will not sleep well that they become tense as bedtime approaches. These fears may sometimes be put to rest by the knowledge that sleep needs vary greatly from individual to individual. In some cases, people may not physiologically require a “normal” amount of sleep but have been convinced that they have a sleep disorder by spouses who do. Another commonly held misperception that contributes to tension is the notion that, once sleep is lost, it can never be recovered. Studies have shown that sleep-deprived humans are able to return quickly to normal sleep patterns, and therefore a few nights of poor sleep is no cause for alarm.

For those whose anxiety about sleep persists, techniques that teach people to relax their muscles or meditation to decrease mental activity may reduce this anxiety and promote sleep. Patients who experience better sleep when away from their normal sleeping location may have “learned” to associate the bedroom environment with wakefulness. To overcome this problem, stimulus control is used to try to strengthen the bedroom as a cue for sleep. This method requires that patients use the bedroom only for sleeping and go to bed only when sleepy. Most important, if they do not fall asleep within ten minutes of lying down, they should get up, go into another room, and engage in a mundane activity, coming back to the bedroom only when sleepy. This may be done several times, but the main goal is to associate the bedroom with falling asleep quickly. Regardless of the length of sleep, patients should always get up at the same time and not nap during the day. This regimen may need to be continued for several weeks in order to overcome the previous habit and requires perseverance from the patient; however, the advantage of
behavioral therapy lies in the absence of the side effects caused by medication.

Excessive daytime sleepiness is usually diagnosed by a polysomnogram followed by a Multiple Sleep Latency Test. In this test, patients are allowed to fall asleep several times a day, and if sleep occurs within five minutes multiple times during the day, the diagnosis is positive. EDS is treated in different ways depending on its cause. If the cause is sleep apnea or periodic leg movements, the disorder is handled as described above. In other cases of sleep fragmentation, medication is used to prevent arousal during the night. The excessive daytime sleepiness found in narcoleptics is usually treated with drugs that act as central nervous system stimulants. Other symptoms of
narcolepsy are usually treated with antidepressant drugs that suppress REM sleep. Of these, gamma hydroxybutyrate has been shown to be effective and to cause limited side effects. Short naps taken throughout the day seem to prevent many of the symptoms associated with sleep attacks.

Problems with the circadian rhythms of the sleep-wake cycle are usually not helped by medication. Instead, chronotherapy may be effective in resetting the biological clock. Over the course of two weeks, the patient’s bedtime is gradually moved forward or backward around the clock until the desired bedtime is reached. Similar effects may be seen using strong light to shift the sleep period.

Perspective and Prospects

The field of sleep research is still in its infancy. For most of history, sleep was not studied at all because it was difficult to characterize the process without interrupting it. Early scientists such as Lucretius, however, made observations and suggested that the motions of sleeping animals might reflect their dreams. In the early nineteenth century, sleep was viewed simply as the absence of waking, and the treatment of lethargic patients with damage to the brain stem led doctors to postulate that this area of the brain had two centers—a waking center and a sleeping center. These two centers were thought to function and communicate with each other using chemical signals. As the field of neurobiology advanced, it became possible to measure the electrical properties of the brain using an electroencephalograph. By the 1930s, numerous studies had shown that the brain remains active during sleep and that the different stages of sleep have different patterns of electrical activity. REM sleep was first observed in 1953 and was linked to dreaming. Additional brain structures in the midbrain and pons were identified that controlled REM and non-REM sleep. An understanding of the neurotransmitters, or chemical substances involved in sleeping and waking, began in the 1960s when it was discovered that neurons in the pons contained serotonin and norepinephrine. Another neurotransmitter, acetylcholine, was found in neurons that were active during REM sleep.

It is only recently that the study of sleep disorders has been recognized as a legitimate pursuit. Most of the sleep disorders mentioned here were discovered in the 1960s and 1970s, and public opinion regarding those who complain of tiredness and fatigue has only gradually shifted from disdain to understanding that there might be a real physiological cause.

This greater acceptance might be due to a growing awareness of the toll of sleep deprivation. It is now understood by medical officials that the consequences of sleep deprivation are more severe than most people realize and affect metabolism, endocrine functions, immune system function, memory, mood, and reaction time. The average adult sleeps about an hour less than the eight hours per night recommended by sleep experts. Many people often stay up later than they should because of watching television or surfing the Web. Insomnia is experienced by more than half of the adult population at some point in their lives, and more than 10 percent of the population experiences restless leg syndrome. The factors most often identified for disrupting sleep are stress and pain. Despite sleep deprivation, many people will still strive while drowsy, and some have even fallen asleep at the wheel. Sleep deprivation has also negatively impacted work performance for numerous adults. The list of work-related problems includes being late for work, making errors, reductions in the quality of work, lower productivity, diminished concentration, and suffering injuries.

Perhaps because of such statistics and a growing public recognition of the dangers of sleep problems, the number of sleep centers and laboratories that are studying sleep and its accompanying disorders has grown tremendously. These sleep centers have been instrumental in elucidating the primary disorders of sleep and in educating the general public concerning sleep management and the safety risks that result from abnormal sleep. Research laboratories are investigating the anatomical, chemical, and physiological mechanisms of sleep and sleep abnormalities. Some of the most interesting areas of research include genetic studies that determine whether sleep disorders are inherited. There appears to be a significant genetic component to several sleep characteristics, including bedtime, sleep duration, insomnia, narcolepsy, snoring, and sleep apnea. It is expected that, as scientists come to understand more about the nature and mechanisms of the brain and normal sleep, further understanding of the causes and treatments for sleep disorders will be forthcoming.

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Caldwell, J. Paul. Sleep: The Complete Guide to Sleep Disorders and a Better Night’s Sleep. Rev. ed. Toronto, Ont.: Firefly Books, 2003.

Carskadon, Mary A., ed. Encyclopedia of Sleep and Dreaming. New York: Macmillan, 1993.

Dement, William C., and Christopher Vaughan. The Promise of Sleep. New York: Delacorte Press, 1999.

Dotto, Lydia. Losing Sleep: How Your Sleeping Habits Affect Your Life. New York: William Morrow, 1990.

Hobson, J. Allan. Sleep. New York: Scientific American Library, 1995.

Montplaisir, Jacques, and Roger Godbout, eds. Sleep and Biological Rhythms. New York: Oxford University Press, 1990.

Pollak, Charles P., Michael J. Thorpy, and Jan Yager. The Encyclopedia of Sleep and Sleep Disorders. 3d ed. New York: Facts on File, 2010.

Reite, Martin, John Ruddy, and Kim E. Nagel, eds. Concise Guide to Evaluation and Management of Sleep Disorders. 3d ed. Washington, D.C.: American Psychiatric Press, 2002.

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Walsleben, Joyce A., and Rita Baron-Faust. A Woman’s Guide to Sleep: Guaranteed Solutions for a Good Night’s Rest. New York: Crown, 2001.

What is rule-governed behavior? |

Introduction

Following the tradition of B. F. Skinner, the famous Harvard
University psychologist who pioneered the study of operant
conditioning, behavior analysts initially examined the
behavior of rats and pigeons because nonhuman subjects could be studied under
well-controlled conditions in the experimental laboratory. This made it possible
for operant psychologists to discover a number of important behavioral principles
and to demonstrate that much of the behavior of their experimental subjects was
shaped and maintained by contingencies of reinforcement. “Contingencies” can be thought of as
cause-effect relations between a context (in operant terms, a “discriminative
stimulus”), an action (“response”), and the consequence (“reinforcement”)
it produces. For example, if pressing a bar is followed by food only when a light
is on and never when it is off, a rat’s behavior is gradually shaped by these
contingencies until the rat presses the lever only when the light is on.

When operant researchers began to bring human subjects into the laboratory,
however, the analysis went beyond behavior directly shaped by contingencies to
include behavior under the control of instructions or rules. According to Skinner,
a rule is a “contingency-specifying stimulus.” It functions as a discriminative
stimulus (SD), but it differs from other SDs in that it is a
description of a behavior-outcome relation. Other SDs are
stimuli in the environment that acquire control over behavior only through
specific training; rules, in contrast, have an immediate effect on behavior
because they make use of an already existing language repertoire. For example,
through a history of careful shaping, a seeing-eye dog can be trained to stop at red lights and
cross the street only when the light is green. A verbal child, however, can be
taught the same discrimination simply by being told, “Go when the light is green;
don’t go when the light is red.”

Proverbs, maxims, advice, instructions, commands, and so forth all function as
rules when they control behavior. In complete form, rules specify an antecedent
condition, an action, and its consequences, and often take the form of if-then
statements, as in “If you want to get to the other side safely, then cross the
street only when the light is green.” Most rules, however, are only partial
statements of contingencies, specifying exclusively the antecedent (such as a male
figure or the word “men” on a door), the behavior (a sign reading do not enter),
or the consequence (“Lose twenty-five pounds in one month!”), and it is left to
the individual to fill in the blanks.

Despite an abundance of rules in the human environment, many people are not
reliable rule-followers. Control by rules is often deficient because rules only
determine the topography, or form, of behavior, but they do not impart the
motivation to act. Stated differently, rules tell people
what to do, but whether people actually do it depends on other circumstances.

Role of Contingencies

For a rule to be followed, it must be part of an effective contingency: Either
the outcome specified in the rule must function as a reinforcer, or the rule giver must be able to
mediate aversive consequences (punishment) for noncompliance.
Psychologists Steven C. Hayes and Robert D. Zettle have drawn an important
distinction between contingency-shaped and rule-governed behavior. They assert that
contingency-shaped behavior is controlled by one set of contingencies, usually
consisting of a situation, an action, and a consequence (such as being offered a
beer, drinking, and feeling relaxed).

In contrast, rule-governed behavior involves two sets of contingencies. One of them is the behavior-outcome relation specified in the rule itself (“If you want to avoid addiction, just say no”). The second involves social consequences for rule following, such as praise or criticism from significant others or social pressure to comply with peer norms. As the following examples will show, at times both sets of contingencies support rule following, but sometimes they compete with each other. In one example, a man is lost and his wife insists that he ask for directions. He is told to “turn left at the light and then follow the signs to the interstate.” The man is likely to follow these directions, because both sets of contingencies surrounding rule following are congruent: The natural consequences of finding the highway are indeed reinforcing to him, and the social consequences are reinforcing because following the directions will satisfy his wife and spare him criticism. In another example, however, a child is given a box of candy. Her mother says, “You may have only one piece of candy before dinner, or else you will spoil your appetite.” The contingency specified in the rule may be ineffective, because eating only one piece of candy if there is more may never have been reinforcing to the child. Hence, if the child obeys, it is not for the contingency specified in the rule but for the parental consequences that would result from noncompliance.

Behavior under the control of a description of contingencies does not involve a
new process but is consistent with an operant framework postulating that the
probability of behavior is controlled by its outcome. Rule governance results from
an extensive history of reinforcement in which rule-following has directly led to
contact with the contingencies specified in the rule, to social consequences
associated with compliance and noncompliance, or both.

Role in Learning

Teaching people to follow rules is important for a number of reasons, which B.
F. Skinner outlined in his book About Behaviorism (1974). Most
important, many behaviors can be acquired much more quickly through rules than
through shaping by the contingencies described in the rules. For example, it is
easier to teach a boy the basics of a card game by explaining the rules to him
than by playing with him until he gradually (if at all) figures out the rules for
himself. Furthermore, there are cases when the contingencies are so complex or
vague that most people would never understand them without the help of rules.
Learning to type with ten fingers illustrates such a case. Without appropriate
instruction, the immediate success accruing from a hunt-and-peck method will
reinforce typing with two fingers, and the person will never learn to use ten
fingers, even though in the long run this would have been much more efficient.

According to Roger L. Poppen in a 1989 essay, initially people learn rules from
a multitude of external sources such as parents, peers, teachers, television, and
books, and eventually they learn to extract rules from interacting with and
observing environmental contingencies. Parents encourage the rehearsal and
internalization of rules so that these self-instructions then help children guide
their own behavior in similar circumstances.

Behavior-Analytic Theory

The effects of rules on behavior have been extensively studied within a
behavior-analytic methodology. A summary of this research can be found in a
chapter by Margaret Vaughan in the book Rule-Governed Behavior:
Cognitions, Contingencies, and Instructional Control, edited by Steven
C. Hayes (1989). Most of these human operant studies use a method in which
subjects press a button that, according to some schedule of reinforcement (an
arrangement that specifies which responses within an operant class will be
reinforced), occasionally produces points exchangeable for money. Depending on the
preparation, button pressing may be controlled by the contingency between pressing
and point delivery; in this case, the behavior would be contingency-shaped. Button
pressing may also be controlled by experimenter instructions, in which case the
behavior would be rule-governed.

A number of studies showed that experimenter-provided instructions quickly
bring the behavior under stimulus control (behavior occasioned by a stimulus because the
stimulus signals some consequence of responding) but also create insensitivity to
the scheduled contingencies. For example, telling subjects that “the best way to
earn points is to press the button fast” (a fixed-ratio contingency) immediately
allows them to respond correctly and earn points. When the contingencies are then
surreptitiously changed, however, subjects continue to follow the instructions for
long periods of time although they have become obsolete and no longer produce
rewards. In contrast, when subjects receive no instructions and their responses
are shaped, sensitivity to changing contingencies develops; that is, when the
schedule of reinforcement changes, subjects adjust their behavior to the new
schedule and continue to earn points. This observation has led operant researchers
to conclude that insensitivity to contingencies may be an inherent property of
instructional control.

Effect of Irrational Beliefs

The insensitivity effect of rules has intriguing implications: Instructing
people how to solve problems is immediately effective, but it may be
counterproductive in the long run, because individuals may come to act in
accordance with outdated rules. Their behavior may come to be guided by what
cognitive psychologists call irrational beliefs or unrealistic expectations, which
from an operant
perspective would be considered inaccurate statements about contingencies
resulting from broad overgeneralizations of old rules. The following example
illustrates how an irrational belief may come to control behavior. A mother might
tell her child, “Stop making noise! I don’t love you when you are bad.” This rule
may quiet the child immediately, and because it is effective, the parent may use
it in other situations. Over the course of her development, the child learns many
instances of what her parent considers “bad” (perhaps disobeying instructions,
perhaps asserting herself, showing anger, and so on). Gradually she internalizes a
generalized rule, “I am only lovable when others approve of me,” and evolves into
an adult who tries to please everybody and feels unworthy at any sign of
disapproval, however ineffective this behavior may be.

Humans live in a world in which rules abound, in the form of instructions,
advice, warnings, manuals, cookbooks, self-help books, laws, and social norms.
They are intended to provide guidelines for effective behavior. Even when no
external rules are available, most people can formulate their own plans of action.
The greatest advantage of rules is that they can be extremely helpful and can
establish effective behavior quickly. Their greatest disadvantages are that rules
do not produce behavior unless other contingencies support rule following and (as
Skinner has pointed out) that they may be troublesome rather than helpful when the
contingencies change but the rules do not.

Evolution of Study

Originally, behavioral researchers attempted to replicate findings from
experimental work with rats and pigeons to demonstrate the generality of the
principles of behavior discovered in the animal laboratory. It soon became
apparent that people often showed response patterns not comparable to those of
animal subjects on the same schedules of reinforcement. For example, a cumulative
record of responding on a fixed-interval schedule for animals typically shows
“scallops” (a pause after reinforcement, followed by a gradually accelerating
response rate until delivery of the next reinforcer). In contrast, human subjects
typically time the interval by counting; toward the end, they respond as few times
as necessary to obtain the reinforcer.

Behavior analysts suspected that the differences between human and animal
responding mainly stemmed from people’s prior conditioning history and from instructions,
both experimenter-provided and self-generated, with which they approached the
experimental tasks. These assumptions began to focus the attention of operant
researchers on the role of instructions. By the mid-1970s, instruction following
became synonymous with rule-governed behavior and began to evolve into a field of
study in its own right.

Importance of Approach

One importance of rule governance lies in the possibility of a rapprochement
between behaviorist and cognitivist positions. Behaviorists have often been
accused of disregarding or failing to acknowledge the importance of higher mental
processes. Although such accusations are polemic and extremely misleading, it is
true that it was not until the mid-1970s that operant psychologists began a
systematic empirical analysis of cognitive-verbal processes. The study of
rule-governed behavior marked the beginning of the experimental analysis of
phenomena that until then pertained to the domain of cognitive
psychology.

The analysis of rule-governed behavior is important for another reason. It
provides some insights into causal mechanisms that may underlie current cognitive
therapies. For example, in 1987 Poppen presented an excellent theoretical analysis
of a self-efficacy approach and of rational emotive therapy,
while in 1982, Zettle and Hayes presented a similar analysis of cognitive
restructuring and cognitive therapy for depression. The common denominator of
these diverse cognitive approaches is their assertion that people’s reactions to
their environment are mediated by covert verbal statements, which, when
dysfunctional, are given labels such as irrational beliefs, low self-efficacy, and
negative expectancies. From an operant perspective, such formal categorizations
are considered not very useful because formally distinct verbal statements may all
have the same function, while statements identical in form may have different
functions (one person might say “I can’t do it; I’m too dumb” to avoid an
unpleasant task, while another person may say the same thing to request
assistance).

Within a framework of rule-governed behavior, all these dysfunctional
cognitions are considered partial statements of contingencies, and the behavior
they produce is rule-governed. Hence, findings from basic experimental research on
rule-governed behavior could conceivably be brought to bear on clinical phenomena,
which eventually might lead to a better understanding of psychological
dysfunctions and to the development of more effective therapies.

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Freeman, Arthur,
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O'Hora, Denis, Dermot Barnes-Holmes, and Ian
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Pierce, W. David, and Carl D. Cheney.
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and Steven C. Hayes. “Rule-Governed Behavior: A Potential Theoretical
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Kendall. Vol. 1. New York: Academic, 1982. Print.

We have seen how the Spanish conquistadors were able to bring down large empires in North and South America with a handful of men. Jared Diamond...

This is, of course, a matter of opinion and conjecture as nothing like this has happened in any culture in a very long time and nothing even remotely like this has ever happened to the United States.  My own view is that the answers to these two questions depend very much upon the exact circumstances in which we found ourselves.

In general, I believe that we would have a better chance at mounting a defense and at holding our society together than the Aztecs or the Inca did.  This is because elites do not dominate our society in the same way that they dominated those societies.  For example, imagine that the president and half of Congress died.  This would disrupt things of course, but we would have many other leaders who would be ready to step in.  We would not descend into Civil War over who the next president would be because we have laws that govern these sorts of things.  We would not be lost because there are any number of our citizens who could step into government positions and be able to lead.  Our culture is more democratic than theirs and so the deaths of half of our leaders would not impact us as much as it impacted them.

Looking at specific situations, I believe that we would be more able to mount a defense if we knew the cause of the deaths.  If people just seemed to be dying at random, with no symptoms, it would surely cause panic.  However, if people started dying from disease, it would not destroy our social fabric as badly as it did that of the Incas or Aztecs.  We would be able to understand what caused the disease.  We would have a hope of finding a cure.  We would not be helpless like people were in those days, thinking only that it was the will of the gods that people were dying.  So, the more we knew about why people were dying, the better our society would hold together, even if we had not yet found a way to prevent the deaths.

In addition, our ability to mount a defense would depend tremendously on the power of the invaders.  We would surely be destroyed if we had people invade us, say from outer space, who were as far ahead of us in technology as Europeans were ahead of the Native Americans.  We would be able to mount a defense, but it would not matter all that much because even our best defense would not be able to prevail against them.  However, if we were attacked by someone more on our own level, I would think that we would be able to defend relatively well because we would still be motivated to repel them (unless we thought they could prevent the deaths, in which case we would probably give in).

In general, then, I think that our society would not be as badly affected by these deaths as the Incas and the Aztecs were.  This may simply be my own bias because I think we are so much more advanced than they were in every way.  I believe that our social fabric would not be ripped apart as much as theirs because we have much more scientific knowledge and we have a society that is much less dominated by political and religious elites.

What is congenital heart disease?

Causes and Symptoms

Congenital heart disease
includes various structural and functional defects of the heart and blood vessels resulting from errors that occur during
embryonic development. The defects may cause heart murmurs, high or low blood pressure, congestive heart failure, cyanosis (blue skin), abnormal heart rhythms and rates, and incidences of low oxygen (hypoxia). Congenital heart disease is detected in about 0.7 percent of live births and more than 10 percent of stillbirths. Some babies born with congenital heart disease have difficulty during the first few weeks of life. Some problems, however, are not easily detected at the time of birth and are discovered at various stages of life. Heart defects may be inherited from parents, induced by environmental agents such as drugs, or caused by an interaction of genetic and environmental factors. Defects are more common in children with genetic disorders such as Down syndrome. With intensive treatment, including surgery, many forms of congenital heart disease can be corrected, allowing those affected to lead normal lives.

Knowledge of normal heart development will help in understanding how congenital heart disease occurs and will provide a means for categorizing these defects. Near the end of the third week of embryonic development, the heart begins to form from two cords of tissue that hollow out and fuse to form a primitive heart tube. This tube undergoes some constrictions and dilations to form the early divisions of the heart, including a receiving chamber, the atrium, and a pumping chamber, the ventricle, which exits into a muscular tube called the truncus arteriosus. At about twenty-two days, the heart begins to contract and pump blood. A day later, it bends or loops upon itself to form an S shape, with the atrium on one side, the truncus arteriosus on the other side, and the ventricle in the middle. If it bends to the left instead of to the right, a rare heart defect called dextrocardia results. The heart will be displaced to the right side of the body and may have some accompanying abnormalities.

During the fourth and fifth week of development, the heart begins to divide into four chambers by first forming a septum (dividing membrane) in the canal between the atrium and the ventricle. This septum is formed by heart tissue called the endocardial cushions. Failure of this septum to form properly causes atrioventricular canal defects. These are often associated with Down syndrome. During the fifth week of development, a spiral septum forms in the truncus arteriosus that divides it into two vessels: the
pulmonary artery, which connects to the right ventricle, and the aorta, which connects to the left ventricle. The formation of this septum and the ventricular connections are subject to error and may result in a group of anomalies called conotruncal defects.

As these large arteries are forming, a shunt (bypass) develops between them called the ductus arteriosus. This short vessel allows the blood to be diverted away from the nonfunctional fetal lungs into the aorta and on to the placenta, where it will receive oxygen and nutrients. Persistence of this shunt after birth is responsible for a defect called patent ductus. A septum dividing the atrium into right and left halves also forms during the fourth and fifth weeks of development; however, blood is allowed to pass from the right atrium to the left atrium through a small hole in this septum called the foramen ovale. This hole normally closes after birth but is necessary during fetal life to shunt blood away from the fetal lungs and toward the placenta in a manner similar to that of the ductus arteriosus. At about the same time, a septum forms from the floor of the ventricle and divides it into right and left halves. Failure of the atrial and ventricular septa to form properly and to close at the time of birth results in septal defects.

After the appearance of the four chambers, two pairs of valves form in the heart to prevent the backflow of blood and to ensure greater efficiency in pumping. The semilunar valves (also called the pulmonary and aortic valves) form between the ventricles and their respective outlet arteries (pulmonary artery and aorta), and the atrioventricular valves (bicuspid or mitral on the left and tricuspid on the right) form between the atria and the ventricles. Improperly formed valves can lead to flow defects. During development, the heart also makes connections with veins returning from the general
circulation and the lungs. Errors in these connections and other structural errors cause several other less common congenital heart defects.

The most common congenital heart defects are the septal defects and patent ductus, which together account for about 37 percent of all heart defects. After birth, because the pressure becomes higher in the left side of the heart, blood moves from left to right through the openings in the heart that come with such defects, causing too much to flow to the lungs and a mixing of systemic and pulmonary blood. The child’s lungs will be congested, causing difficulty in breathing and eventually heart failure.

About 29 percent of congenital heart defects are categorized as right-heart and left-heart flow defects. These defects impede the flow of blood from either the right or the left side of the heart to its normal destination. Right-heart flow defects include bicuspid pulmonary valve (a valve with two cusps instead of three), pulmonary valve
stenosis (a narrowing of the valve), dysplastic pulmonary valve (a malformed valve), peripheral pulmonary stenosis (a narrowing of the walls of the pulmonary artery), infundibular pulmonary stenosis (a narrowing below the valve), and hypoplastic right ventricle (incomplete formation of the valve). These defects impede blood flow to the lungs, which results in poor oxygenation of the blood (cyanosis). Left-heart flow defects include bicuspid aortic valve, aortic valve stenosis, coarctation of the aorta (narrowing), aortic atresia (a blocked aorta), and hypoplastic left ventricle. These defects impede blood flow to the body and often result in altered blood pressure, hypoxia of body tissues, and congestive heart failure.

The principal conotruncal defects, which account for about 17 percent of heart defects, are tetralogy of Fallot and transposition of the great arteries. Tetralogy of Fallot includes four defects that result in cyanosis: pulmonary stenosis, a ventricular septal defect, an overriding or displaced aorta, and hypertrophy or enlargement of the right ventricle. With transposition of the great arteries, the aorta connects to the right ventricle and the pulmonary artery to the left ventricle, the opposite of the normal formation. The blood is not properly oxygenated, and survival is not possible without medical intervention or a natural shunt such as patent ductus. Other rare conotruncal defects include double outlet right ventricle (the aorta and the pulmonary artery attached to right ventricle), truncus
arteriosus (failure of the truncus to separate into the aorta and the pulmonary artery), and aortopulmonary window (an opening between the aorta and the pulmonary artery).

Defects resulting from improper fusion of the endocardial cushions and surrounding tissues cause atrioventricular defects, which affect about 9 percent of congenital heart disease cases. Complete atrioventricular canal defect occurs in about 20 percent of Down syndrome cases, but it is rare outside this group. The defect produces a large open space in the center of the heart, allowing blood to intermix freely between the right and left sides of the heart. The defect is sometimes accompanied by hypoplastic ventricle. If the condition is not treated, the heart will fail. Patent foramen primum or ostium primum is a milder form of atrioventricular canal defect in which the atrial septum fails to fuse with the endocardial cushions, resulting in a problem similar to atrial septal defect. In addition, the mitral valve is usually deformed.

Other less common defects include looping defects such as dextrocardia, in which the apex of the heart points to the right instead of to the left. This change in symmetry normally does not affect heart function, but some looping defects are associated with other problems such as transposition of the great arteries. Another less common defect is anomalous venous return, in which the veins returning blood to the heart from the lungs attach to the right atrium or return to the right atrium by attaching to other large veins rather than to the left atrium. Errors in the coronary artery connections may also occur, causing poor circulation of blood to the heart muscles. Very rarely, the heart may protrude through the chest wall at birth, causing a difficult-to-treat problem called ectopia cordis.

Treatment and Therapy

Congenital heart disease can often be diagnosed shortly after birth, especially if the baby experiences certain symptoms such as cyanosis, shortness of breath, fatigue and sweating while eating, and inability to gain weight. A physical examination by a physician will include checking the heart and breathing rates for abnormalities and listening to the heart for possible murmurs. Heart murmurs are whooshing sounds caused by turbulent movement of blood that may indicate faulty valves, patent ductus, and other heart defects. A cardiologist will make the definitive diagnosis by administering such tests as the electrocardiogram, the Doppler-echocardiogram, and the cardiac catheterization. The electrocardiogram measures the rhythmic electrical signal that passes through the heart with each beat. An abnormal signal will often indicate problems with a particular region of the heart and is especially useful in identifying rhythm disorders. The echocardiogram produces visual images of the heart by sending out ultrasound waves that bounce off and return to a receiving device. Most structural heart defects can be detected with this technique, and many are discovered prenatally with routine fetal ultrasound monitoring. At the same time, a second receiving device (the Doppler) analyzes ultrasound signals from blood moving through the heart and is able to provide information about the speed and direction of blood flow within the heart. This helps detect abnormal functions such as reverse blood flow. The Doppler-echocardiogram has revolutionized congenital heart disease diagnosis and, in most cases, provides enough information to define the patient’s problem accurately.

If the cardiologist believes it to be necessary, then further tests can be done. A chest X-ray may be taken to determine if there is any lung involvement in the disorder. Cardiac catheterization can add information about the internal heart blood pressures and blood oxygen levels and can help visualize some defects better with the administration of contrast dyes in combination with X-ray analysis. Special monitors can be used to record the electrocardiogram for one or two days to check for intermittent rhythm irregularities, and older children can be monitored while exercising to see how the heart performs under stress. These and other tests allow physicians to assess the seriousness of the problem and to recommend timely and appropriate treatment.

Serious heart malformations need to be treated immediately upon diagnosis. Often these include defects that cause cyanosis, including transposition of the great arteries, left-heart flow defects such as coarctation of the aorta, and defects that cause heart failure, such as truncus arteriosus. Immediate emergency surgery may be needed to save the life of the newborn infant. Additional follow-up surgeries may also be required to correct the defect completely. For example, one way of correcting transposition of the great arteries is by performing an atrial switch operation in which systemic blood returning from the body is diverted to the left side of the heart (so it can be pumped to the lungs) and pulmonary blood from the lungs is diverted to the right side of the heart (so it can be pumped to the body). This is accomplished by first enlarging the foramen ovale with a balloon catheter, a procedure called Rashkind balloon atrial septostomy. A second operation several months later enlarges the opening between the two atria further and installs a flap to enhance the cross flow of blood. This is known as a Mustard or Senning atrial switch operation. A more recently developed procedure for correcting this defect requires only one operation. The
misplaced aorta and pulmonary artery are both cut and then reattached to the correct heart chamber; this is called a Jatene arterial switch operation. At the same time, the coronary arteries are moved to the new aorta.

Some defects require no surgery but can be treated with drugs and other less traumatic procedures, such as the
balloon catheter. Drugs are also used to help improve heart performance before and after surgery. When fluid accumulates in the lungs or other body tissues, the heart has problems pumping all the blood that returns to it because of the congestion. The overworked heart suffers under this stress, and thus the condition is called congestive heart failure. Diuretics such as Lasix (furosemide) improve the kidneys’ ability to remove the excess fluid and relieve the congestion. Another drug, digitalis, can be helpful in treating congestive heart failure by slowing the heart rate and causing the heart to beat more forcefully. An open ductus is beneficial to children born with cyanotic heart defects because it allows a more even distribution of oxygenated blood. Treatment with prostaglandin E1 helps to keep the ductus open until corrective surgery can be performed. Indomethacin has the opposite effect and is often used to promote closing of a patent ductus in premature babies. As in adults, drugs such as digitalis, beta-blockers, and calcium channel blockers can be used to treat abnormal heart rhythms (arrhythmia) in children with congenital heart disease. The
balloon catheter is used to enlarge narrow vessels and passages and has been used successfully to treat pulmonary and aortic valve stenosis in a technique called balloon valvuloplasty.

Types of surgery done later in infancy or childhood include closed-heart operations such as repair of a patent ductus and partial treatment of some types of cyanosis with a Blalock-Taussig shunt (connecting the subclavian artery to the pulmonary artery to bring more blood to the lungs).
Open-heart surgery is used to repair defects inside the heart such as septal defects. A heart-lung machine is used to bypass the heart and lungs while the operation is under way, and the body is cooled so that the brain and other tissues require less oxygen. Children with very serious heart defects such as hypoplastic right or left ventricles may require a series of corrective surgical operations, and for some the only hope is a heart transplant. For example, children with hypoplastic right ventricle are given a Blalock-Taussig shunt shortly after birth to improve blood flow to their lungs and then are later given the Fontan operation, which involves closing off the Blalock-Taussig shunt and connecting the pulmonary artery to the right atrium so that blood returning from the body will flow directly to the lungs, completely bypassing the defective right ventricle.

Some heart defects require no treatment. For example, most small septal defects close on their own during the first one or two years of life. Also, mild disorders such as benign valve defects usually require no treatment, and many children with heart murmurs have no detectable problems.

Perspective and Prospects

In the late nineteenth and early twentieth centuries, physicians were beginning to understand that certain congenital heart defects such as patent ductus could be diagnosed by listening to the heart. Treatment, however, was not possible at that time. The Atlas of Congenital Cardiac Disease was published in 1936 by Maude Abbot of McGill University. This manual greatly assisted physicians in recognizing and diagnosing congenital heart disease. In 1939, Robert Gross of Boston repaired a patent ductus, and in 1944, Alfred Blalock and Helen Taussig developed and performed their shunt operation in order to treat children with tetralogy of Fallot. Open-heart surgery was not performed until the mid-1950s, when the heart-lung machine was perfected. Even then, open-heart surgery could be performed only on older children. These operations were pioneered by Walton Lillehei of the University of Minnesota and John Kirlin of the Mayo Clinic. Open-heart surgery on newborn infants was developed in the 1970s by Brian Barratt-Boyes of New Zealand.

During the period while heart surgery was being developed, cardiac catheterization was also advancing. It was used primarily for diagnosis, but in 1966, William Rashkind of Philadelphia began to use the balloon catheter to enlarge openings in the atrial septum in order to treat transposition of the great arteries. Microsurgical catheters are currently being developed to repair patent ductus and other heart defects without the need for major surgery. The echocardiogram was pioneered by Inge Edler in the 1950s, and the Doppler-echocardiogram came into widespread use as a diagnostic tool in the 1980s. This instrument has greatly reduced the need for other diagnostic tests that were used in the past.

The modern strategy for treatment of congenital heart defects is to perform the corrective surgery as early in infancy as possible. This eliminates the need for numerous hospitalizations and diagnostic tests and reduces the need for extensive drug treatment. Children with multiple defects may still need more than one surgery. Modern treatment also emphasizes the roles of the child, the family, and health care personnel in fostering an understanding of the condition, treatment, and outcome. Even children who have been successfully treated will sometimes have physical limitations. These children need to be encouraged and supported by their families and allowed to pursue their goals to the fullest extent possible. Overcoming congenital heart disease is now possible for the vast majority of those who are afflicted.

Bibliography:

"Congenital Heart Disease." Medline Plus, December 5, 2011.

Gersh, Bernard J., ed. The Mayo Clinic Heart Book. 2d ed. New York: William Morrow, 2000.

Koenig, Peter, Ziyad M. Hijazi, and Frank Zimmerman, eds. Essential Pediatric Cardiology. New York: McGraw-Hill, 2004.

Kramer, Gerri Freid, and Shari Mauer. Parent’s Guide to Children’s Congenital Heart Defects: What They Are, How to Treat Them, How to Cope with Them. New York: Three Rivers Press, 2001.

Moore, Keith L., T. V. N. Persaud, and Mark G. Torchia. The Developing Human: Clinically Oriented Embryology. 9th ed. Philadelphia: Saunders/Elsevier, 2011.

Neill, Catherine A., Edward B. Clark, and Carleen Clark. The Heart of a Child: What Families Need to Know About Heart Disorders in Children. 2d ed. Baltimore: Johns Hopkins University Press, 2001.

Park, Myung K. The Pediatric Cardiology Handbook. 4th ed. St. Louis, Mo.: Mosby/Elsevier, 2010.

Porter, Robert S., et al., eds. The Merck Manual of Diagnosis and Therapy. 19th ed. Whitehouse Station, N.J.: Merck, 2011.

Sherwood, Lauralee. Human Physiology: From Cells to Systems. 8th ed. Pacific Grove, Calif.: Brooks/Cole, 2012.

Pick out several points that build up the idea of comfortable routine and a genuine looking forward to her husband's return.

Pretty much everything in the story paints a picture of a peaceful routine, all the way up until the husband reveals how tired he is (which he usually doesn't do) and when he consumes his drink faster than usual. I'll pull out some particularly quotable details and put them in bold text below.

To begin, the second paragraph of the story is filled with details that lead us to believe that Mary is happily, calmly...

Pretty much everything in the story paints a picture of a peaceful routine, all the way up until the husband reveals how tired he is (which he usually doesn't do) and when he consumes his drink faster than usual. I'll pull out some particularly quotable details and put them in bold text below.

To begin, the second paragraph of the story is filled with details that lead us to believe that Mary is happily, calmly living out the comfortable routine of waiting patiently for her husband to come home from work:

"Now and again she glanced at the clock, but without anxiety: She merely wanted to satisfy herself that each minute that went by made it nearer the time when he would come home. As she bent over her sewing, she was curiously peaceful. This was her sixth month expecting a child. Her mouth and her eyes, with their new calm look, seemed larger and darker than before."

As you can see here, Mary is sitting comfortably in a chair, feeling calm and happy that her husband will be home soon. Although the narrator doesn't say so explicitly in the above paragraph, we can tell that she probably does this same thing every weekday, since the next paragraph describes a routine:

"When the clock said ten minutes to five, she began to listen, and a few moments later, punctually as always, she heard the car tires on the stones outside, the car door closing, footsteps passing the window, the key turning in the lock. She stood up and went forward to kiss him as he entered."

The description above reveals how these particular actions are part of a well-established routine between the husband and wife. A few paragraphs later, we see some more details about their comfortable evening routine, before the husband starts acting noticeably odd:

"For her, this was always a wonderful time of day. She knew he didn't want to speak much until the first drink was finished, and she was satisfied to sit quietly, enjoying his company after the long hours alone in the house. She loved the warmth that came out of him when they were alone together. She loved the shape of his mouth, and she especially liked the way he didn't complain about being tired."

What is dwarfism? |

Causes and Symptoms

Dwarfism in humans may be caused by a number of conditions that occur either before birth or in early childhood. When short stature is the only observable feature, growth—though abnormal relative to height—is proportionate. Short stature is nearly always attributed to endocrinological dysfunction, but few cases are actually the result of endocrinopathy. If short stature is caused by endocrinopathy, it is often attributable to a deficiency in the pituitary gland (which produces growth hormone) or the thyroid gland. Those who are unusually short but have no other obvious disease are divided into two categories: those who were afflicted prenatally and those who were afflicted postnatally. Many cases are actually the result of chromosomal or skeletal aberrations; other events that may inhibit prenatal growth include magnesium deficiency (which would prohibit ribosome synthesis and, in turn, halt protein synthesis) or a uterus that is too small. Postnatal inhibition of growth may be caused by heredity if both parents are short; there is no skeletal abnormality at fault. Other short-statured children may simply mature at a much slower rate, yet grow normally. Typically, one of the parents may have had a late onset of puberty.

Unusually short-statured males are those who are shorter than sixty inches tall; in females, fifty-eight inches and below is short-statured. Children are classified as dwarfs if their height is below the third percentile for their age. When this is the case, doctors will look primarily to four major causes of dwarfism: an underactive or inactive
pituitary gland, achondroplasia (failure of normal development in cartilage), emotional or nutritional deprivation, or Turner syndrome (the possession of a single, X, chromosome). If the answer is not found in one of these alternatives, then it may be found in rarer causes, either genetically based or disease induced.

Growth hormone, also called somatotropin, determines a person’s height. Growth hormone does not affect brain growth but may influence the brain’s functions. In addition, it may enhance the growth of nerves radiating from the brain so that they can reach their targets. Growth hormone elevates the appetite, increases metabolic rate, maintains the immune system, and works in coordination with other hormones to regulate carbohydrate, protein, lipid, nucleic acid, water, and electrolyte metabolism. Target areas for growth hormone include cell membranes as well as other cell organelles in bone, cartilage, bone marrow, adipose tissue, and the liver, kidney, heart, pancreas, mammary glands, ovaries, testes, thymus gland, and hypothalamus. Fetuses not producing growth hormone still grow normally until birth; they may even weigh more than average at birth. These babies may thrive at first, but if no growth hormone is administered, they will grow to a maximum height of thirty inches. Other telltale physical attributes include higher-than-average body fat, a high forehead, wrinkled skin, and a high-pitched voice. During childhood, there may be episodic hypoglycemia attacks. If the endocrine system is functioning properly, puberty may be delayed but will still occur. Complete reproductive maturity will be reached, and there is great likelihood that the afflicted person will develop his or her complete intellectual potential. When it is inherited, growth hormone deficiency occurs as an autosomal recessive trait. Yet the genetic basis for growth hormone deficiency may not simply be caused by a gene. The condition could, in theory, be the result of a structural defect in the pituitary gland or the hypothalamus, or in the secretory mechanisms of growth hormone itself. Prenatal factors that contribute to the inhibition of growth include toxemia, kidney and heart disease, rubella, maternal malnutrition, maternal age, small uterus, and environmental influences such as alcohol and drug use.

Prenatal thyroid dysfunction that goes untreated results in congenital hypothyroidism

. Children with this disorder do not undergo nervous, skeletal, or reproductive maturation; they may not grow over thirty inches tall. When administered before a child is two months of age, treatment can cause a complete reversal of symptoms. Delayed treatment, however, cannot reverse brain damage, although growth and reproductive organs can be dramatically affected.

Achondroplasia is the most common form of short-limb dwarfism. It is inherited as an autosomal dominant form of dwarfism. Achondroplasia is expressed only when one copy of the gene is present; when an offspring inherits the dominant gene from both parents, the condition is lethal. Incidence of achondroplasia increases with parental age and is more closely related to the father’s age. Mutations may account for a majority of cases of achondroplasia, since there is an affected parent in only about 20 percent of cases. Achondroplasia results from abnormal
embryonic development that affects bone growth; metaphyseal development is prevented, which means that cartilaginous bone growth is impaired. This is accompanied by unusually small laminae of the spine, resulting in spinal stenosis. The spinal cord may become compressed during the normal process of spondylosis. Individuals with achondroplasia may experience slowly progressing weakness of the legs as a result of the spinal cord compression. Achondroplasia is often distinguished by the presence of a disproportionately large head and dwarfed and curved limbs; in addition, an individual may have a prominent forehead and a depressed nasal bridge. A shallow thoracic cage and pelvic tilt may cause a protuberant abdomen. Bowlegs are caused by overly long fibulae. Individuals with achondroplasia who live to adulthood are typically thirty-six to sixty inches tall and have unusual muscular strength; reproductive and mental development are not affected, and neither is longevity.

Marasmus, severe emaciation resulting from
malnutrition prenatally or in early infancy, may be considered a form of dwarfism. It is caused by extremely low caloric and protein intake, which causes a wasting of body tissues. Usually marasmus is found in babies either weaned very early or never breast-fed. All growth is inhibited, including head circumference. If the area housing the brain fails to grow, then it cannot house a normal-sized brain, and the individual may develop an intellectual disability. Infants with marasmus are frequently apathetic and hyperirritable. As they lie in bed, they are completely unresponsive to their environment and are irritable when moved or handled. Although the symptoms are treatable and may disappear, the inhibition of growth is permanent.

Occasionally, dwarfism may be induced by emotional starvation. This type of child abuse causes extreme growth inhibition, inhibition of skeletal growth, and delayed psychomotor development. Fortunately, it can be reversed by social and dietary changes. Children with this form of dwarfism are extremely small but perfectly proportioned; however, they have distended abdomens.

The height achieved in females with
Turner syndrome is typically between fifty-four and sixty inches. Turner syndrome results when an egg has no X chromosome and is fertilized by an X-bearing sperm. The offspring are females with only one X chromosome. These individuals cannot undergo puberty; their ovaries never develop and are unable to function. Physical manifestations of Turner syndrome include short stature, stocky build, and a webbed neck.

Another cause of short stature may be as a consequence of chronic disease. Children with chronic renal
(kidney) failure nearly always experience inhibition of growth because of hormonal, metabolic, and nutritional abnormalities. This occurs more often in children with congenital renal disease than in those with acquired renal disease.

With
congenital heart disease, several factors may prohibit growth. Growth inhibition may be a direct result of the disease or an indirect result of other problems associated with heart disease. These babies experience stress, with periods of cardiac failure, and either caloric or protein deficiency. These conditions slow the multiplication of cells and hence growth. If surgery corrects the condition, some catching up can be expected, depending on how much time has elapsed without treatment.

Treatment and Therapy

The more a child is below the average stature, the greater the likelihood of determining the cause. A child who is short statured should be evaluated so that if an endocrine disorder is the root, the child can be treated. Time is an important consideration with hypothyroidism especially, since the longer it goes untreated, the more likely it is that mental development will be arrested.

Children born with congenital growth hormone deficiency are sometimes small for their gestational age; however, the majority of children with growth hormone deficiency acquire the disorder after birth. For the first year or two, the children grow normally, but growth then dramatically decreases. Diagnosis of growth hormone deficiency requires numerous tests and sampling. If bone age appears the same as the child’s age, then growth hormone deficiency can be eliminated. A test for growth hormone secretion is performed by measuring a blood sample for growth hormone twenty minutes after exercise in a fasting child. If this test shows a hormone deficiency, then growth hormone therapy may allow the child to continue to grow.

At first, growth hormone was harvested from human pituitary glands after persons’ deaths. This process was so expensive, however, that few children with hormone deficiency could be treated. Even worse, some of those who did undergo this treatment were inadvertently infected with a slow-acting virus that proved fatal. In the mid-1980s, it was found that some men who had received human growth hormone died at an early age of a neurological disorder called Creutzfeldt-Jakob disease (CJD). These men were found to have contracted the disease via a growth hormone that had been obtained from pituitary glands during autopsies. Once the relationship was determined, more victims were identified. CJD is a nervous disorder caused by a slow-acting, viruslike particle. Its symptoms include difficulty in balance while walking, loss of muscular control, slurred speech, impairment of vision, and other muscular disorders. Behavioral and mental changes such as memory loss, confusion, and dementia may also occur. The symptoms appear, progress rapidly over the next months, and usually cause death in less than a year. There is no treatment or cure.

These unfortunate circumstances led to the development of a synthetic growth hormone. It is made by encoding bacterial deoxyribonucleic acid (DNA) with the sequence of human growth hormone; the bacteria used are those that grow normally in the human intestinal tract. The bacteria synthesize human growth hormone using the preprogrammed human sequence of DNA; it is then purified so that no bacteria remain in the hormone that is used for treatment. The Food and Drug Administration (FDA) approved the biosynthetic hormone in 1985. The sole difference between the synthetic and the naturally produced growth hormone was one amino acid; in 1987, a new synthetic form without the extra amino acid became available. This synthetic hormone works exactly as natural growth hormone does. Moreover, it does not carry the danger of contamination. In most cases, the patient’s immune system does not interfere with the synthetic growth hormone’s effectiveness.

Those children with various forms of chondrodystrophies (cartilage disorders), such as achondroplasia, are diagnosed using skeletal measurements, clinical manifestations, x-rays, laboratory study and analysis of cartilage, and observed abnormalities of the body’s proteins, such as collagen and cell membranes. In chondrodystrophies, skeletal growth is disproportionate, with shortened limbs more common than a shortened trunk. If visual examination is not confirmation enough, the diagnosis may be assured through x-rays. Although histological studies do not necessarily enhance diagnosis, making an analysis of the patient’s cartilage may lead to a better understanding of the condition. Biochemical studies of abnormal proteins in chondrodystrophies actually have little diagnostic value, but they too may lead to better understanding. Because achondroplasia is genetically inherited, prevention involves genetic counseling before conception.

A child with achondroplasia may be treated symptomatically; surgery on the fibulae to correct bowlegs may be desirable, either for cosmetic reasons or for functional reasons. Laminectomies or skull surgery may be indicated for neurological problems. Orthodontic surgery may be necessary to correct malocclusions and other dental deformities. If hearing loss occurs because of recurrent ear infections, then corrective surgery may be necessary. Individuals with achondroplasia generally enjoy a normal life span, barring complications.

Other chondrodystrophies that cause dwarfism may have more severe symptoms than achondroplasia. Cockayne syndrome, a type of progeria, is the sudden onset of premature
old age in extremely young children. It is the result of inheritance of an autosomal recessive gene. Physical signs of the disease begin after a normal first year of life. In the second year, growth begins to falter, and psychomotor development becomes abnormal. As time passes, dwarfism becomes evident. Other observable characteristics that develop are a shrunken face with sunken eyes and a thin nose, optic degeneration, cavities of the teeth, a photosensitive skin rash that produces scarring, disproportionately long limbs with large hands and feet, and hair loss. The life span for children with this disease is very short.

Another chondrodystrophy inherited through autosomal recessive genes is thanotophoric dwarfism. All known individuals with this condition have died during the first four weeks of life as a result of respiratory distress; most are stillborn. Thanotophoric dwarfism is characterized by an extremely small thoracic cage with only eleven pairs of ribs present. Other physical characteristics of the disease are that the infant has a large skull relative to its face, which is often elongated with a prominent forehead. The eyes are widely spaced, and there is a broad, flat nasal bridge. Frequently, cleft palate is present. The ears are low-set and poorly formed, and the neck is short and fleshy. The limbs, particularly the legs, are bowed; clubfoot is common, as are dislocated hip joints.

A small percentage of short-statured individuals may be unusually short because of social and psychological factors. This condition is called psychosocial dwarfism. This type of nongrowth is secondary to emotional deprivation and is representative of a type of child abuse. The behavior of such children is characterized by apathy and inadequate interpersonal relationships, with inhibited motor and language development. They generally do not gain weight in spite of their extraordinary appetite and excessive thirst; such a child may steal and hoard food yet have the distended abdomen of a starving child. Diagnosis generally identifies a growth hormone deficiency, and when these children are moved to stimulating and accepting environments, their behavior becomes more normal. Their caloric intake decreases as their growth hormone secretion normalizes, and their growth undergoes a dramatic catch-up.

Perspective and Prospects

Because of the complications associated with some forms of dwarfism, medical counseling should begin early. A physical examination should take place in order to determine the type of dwarfism that the child has. If it is ascertained that the short stature cannot be treated, or if the parents and patient choose not to do so, they should be informed of the details of the patient's specific condition and cautioned regarding any future complications that may arise. The patient should be assured that intelligence will not be affected, even if the head is somewhat large. Ear infections are common, and the child should be closely monitored to prevent hearing loss. Normal fertility is the rule, but giving birth will necessitate a cesarean section. In many cases, the child will not be limited physically or mentally as he or she matures. The problems that the patient may face are usually social and emotional; for example, short-statured children may face bullying and discrimination. However, joining nonprofit groups that provide education and support to short-statured individuals may aid children and families in overcoming these difficulties.

Bibliography:

Adelson, B., and J. Hall. Dwarfism: Medical and Psychological Aspects of Profound Short Stature. Baltimore: Johns Hopkins University Press, 2005.

Brooks, S. J., and Robert S. Bar. Early Diagnosis and Treatment of Endocrine Disorders. Totowa, N.J.: Humana Press, 2003.

Juul, Anders, and Jens O. L. Jorgensen, eds. Growth Hormone in Adults: Physiological and Clinical Aspects. 2d ed. New York: Cambridge University Press, 2000.

Kelly, Thaddeus E. Clinical Genetics and Genetic Counseling. 2d ed. Chicago: Year Book Medical, 1986.

Kronenberg, Henry M., et al., eds. Williams Textbook of Endocrinology. 11th ed. Philadelphia: Saunders/Elsevier, 2008.

Little People of America. http://www.lpaonline.org.

Mayo Clinic. "Dwarfism." Mayo Foundation for Medical Education and Research, August 27, 2011.

MedlinePlus. "Dwarfism." MedlinePlus, May 13, 2013.

MedlinePlus. "Growth Disorders." MedlinePlus, May 13, 2013.

Morgan, Brian L. G., and Roberta Morgan. Hormones: How They Affect Behavior, Metabolism, Growth, Development, and Relationships. Los Angeles: Price, Stern, Sloan, 1989.

Shaw, Michael, ed. Everything You Need to Know About Diseases. Springhouse, Pa.: Springhouse Press, 1996.

How does substance abuse affect celebrities?

Substance Abuse Prevalence

Although there have been no scientific studies of how often addictions
occur among celebrities, popular news sources frequently report celebrity arrests for drunk driving, drug possession, public intoxication, and other criminal offenses related to substance abuse. Many celebrities and public figures, including Betty Ford, Elizabeth Taylor, Melanie Griffith, Drew Barrymore, Keith Urban, Eminem, and Ben Affleck, to name just a few, have openly shared their personal stories of struggle with addictions in interviews and autobiographies.

Substance abuse also has been linked to the deaths of many celebrities. Whitney Houston, Michael Jackson, Amy Winehouse, Elvis Presley, Dorothy Dandridge, Marilyn Monroe, John Belushi, Anna Nicole Smith, Janice Joplin, and Heath Ledger are a few examples of celebrities whose deaths involved drug or alcohol overdoses or otherwise harmful combinations of legal and illegal substances.

Other celebrities, such as Lindsay Lohan, Mel Gibson, Robert Downey Jr., and Charlie Sheen, have been in the public eye because of their addictions and substance-abuse-related behaviors. One television reality show, Celebrity Rehab with Dr. Drew (which aired from 2008 to 2012), documented the lives of celebrities seeking inpatient hospital treatment for a variety of addictions. The show ended after its sixth season following the death of a fifth former cast member.

Possible Causes

By the nature of their work, celebrities are subject to public attention and scrutiny. Often, this attention and scrutiny extends beyond celebrities’ work into their personal lives. In 1972 psychologists Thomas Duval and Robert Wicklund proposed self-awareness theory, a framework that may explain why some celebrities abuse substances to cope with excessive attention.

According to self-awareness theory, when persons engage in activities that draw attention to themselves, they often evaluate themselves negatively because their actual lives do not live up to some high internal standard. When this happens, these persons are likely to experience a drop in self-esteem. Researchers who tested self-awareness theory found that people who are more self-focused, as many celebrities can be, are at increased risk for depression, anxiety, and substance abuse. Persons with higher degrees of self-focus also are more likely to have long-lasting negative moods. People may cope with this discomfort by trying to behave in ways that match their internal standards, or they may look for ways to avoid or escape a focus on the self. Some of these escapes include substance use, gambling, sex, shopping, and other addictive behaviors.

Psychologists Jay Hull and Richard Young documented this phenomenon in a 1983 study in which they asked one hundred twenty men age twenty-one years and older to complete a fake IQ test and a real measure of self-consciousness. The researchers then gave the men fake feedback about their IQ test results, telling them that they had scored poorly on the test.

Afterward, the men were asked to participate in a wine-tasting experiment in which they could moderate the amount of wine they consumed. The researchers found that men who were highly self-conscious and received negative feedback on the fake IQ test drank larger quantities of wine than did men who were less self-conscious. These findings support the theory that highly self-conscious people’s alcohol consumption increases in response to a reduction in their self-esteem. It follows that celebrities, whose life experiences force them to be highly self-conscious, also may engage in heavy substance use after receiving negative feedback, such as poor reviews or seeing oneself featured in a tabloid.

Additionally, researchers Lynne Cooper, Michael Frone, and Marcia Russell conducted an online survey and found that both adolescents and adults reported using alcohol both to cope with negative emotions and to increase positive emotions. Additionally, psychological research studies have found that people report increased or inflated self-esteem after consuming alcohol. This research suggests that celebrities may abuse substances as a means to artificially increase their self-perception.

Celebrities also may be likely to abuse substances because of norms of substance use and abuse in celebrity culture. Anthropological research indicates that throughout the world, persons more often than not tend to conform to the accepted social practices and behaviors of their cultures; celebrities are no exception. Young or emerging celebrities may be socialized into a culture in which substance abuse is common, and these celebrities may then later take part in that cultural norm and encourage other celebrities to do the same.

Negative Social Effects

Several research studies have documented that people imitate behaviors they observe in others. In a famous study of observational learning, psychologist Albert Bandura and his colleagues Dorothea Ross and Sheila Ross showed children a film of an adult punching, kicking, beating, and insulting a doll. Children who had observed this aggressive behavior were significantly more likely to engage in aggressive play with the doll, imitating the behaviors of the adult and engaging in new aggressive behaviors.

Many other psychological studies have replicated these results, showing that people learn behaviors, both desirable and undesirable, through watching others. Observing celebrities engage in substance abuse increases the likelihood that members of the general public will imitate this behavior.

Other research in psychology suggests that celebrities are particularly influential role models because they have many of the factors that increase the likelihood of others selecting them as models for observational learning. These factors include attention, high social status, attractiveness, and in some cases, similarity in age, gender, or other characteristics. Additionally, celebrities who abuse substances often face less serious legal and financial consequences for their behavior than do noncelebrities. Therefore, those who are observing celebrity behaviors may be more likely to abuse substances themselves, as they do not see their role models experiencing significant negative consequences for their behavior.

Bibliography

Bandura, Albert, Dorothea Ross, and Sheila A. Ross. “Transmission of Aggression through Imitation of Aggressive Models.” Journal of Abnormal and Social Psychology 63.3 (1961): 575–82. Print.

Cooper, M. Lynne, et al. “Drinking to Regulate Positive and Negative Emotions: A Motivational Model of Alcohol Use.” Journal of Personality and Social Psychology 67.5 (1995): 990–1005. Print.

Duval, Thomas S., and Robert A. Wicklund. A Theory of Objective Self-Awareness. New York: Academic, 1972.

Hull, Jay G., and Richard D. Young. “Self-Consciousness, Self-Esteem, and Success-Failure as Determinants of Alcohol Consumption in Male Social Drinkers.” Journal of Personality and Social Psychology 44.6 (1983): 1097–109. Print.

Ingram, Rick E. “Self-Focused Attention in Clinical Disorders: Review and a Conceptual Model.” Psychological Bulletin 107.2 (1990): 156–76. Print.

Mor, Nilly, and Jennifer Winquist. “Self-Focused Attention and Negative Affect: A Meta-Analysis.” Psychological Bulletin 128.4 (2002): 638–62. Print.

Spradley, James, and David W. McCurdy, eds. Conformity and Conflict: Readings in Cultural Anthropology. 13th ed. Boston: Allyn & Bacon, 2008.