Chapter 17

Anxiety Disorders, Autistic Disorder, Attention-Deficit/Hyperactivity Disorder, and Stress Disorders

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Anxiety Disorders

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• As we saw in Chapter 16, the affective disorders are characterized by unrealistic extremes of emotion: depression or elation (mania).

• The anxiety disorders are characterized by unrealistic, unfounded fear and anxiety.

• Anxiety Disorder

• a psychological disorder characterized by tension, overactivity of the autonomic nervous system, expectation of an impending disaster, and continuous vigilance for danger

With a lifetime prevalence of approximately 28 percent, anxiety disorders are the most common psychiatric disorders.

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Panic Disorder, Generalized Anxiety Disorder, and Social Anxiety Disorder

• People with panic disorder suffer from episodic attacks of acute anxiety—periods of acute and unremitting terror that grip them for variable lengths of time, from a few seconds to a few hours.

• Panic Disorder

• a disorder characterized by episodic periods of symptoms such as shortness of breath, irregularities in heartbeat, and other autonomic symptoms, accompanied by intense fear

• The prevalence of this disorder is approximately 3–5 percent (Schumacher et al., 2011). Women appear to be approximately twice as likely as men to suffer from panic disorder.

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Panic Disorder, Generalized Anxiety Disorder, and Social Anxiety Disorder

• Panic attacks include many physical symptoms, such as shortness of breath, clammy sweat, irregularities in heartbeat, dizziness, faintness, and feelings of unreality.

• The victim of a panic attack often feels that he or she is going to die, and often seeks help in a hospital emergency room.

• Between panic attacks many people with panic disorder suffer from anticipatory anxiety—the fear that another panic attack will strike them.

• Anticipatory Anxiety

• a fear of having a panic attack; may lead to the development of agoraphobia

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Panic Disorder, Generalized Anxiety Disorder, and Social Anxiety Disorder

• This anticipatory anxiety often leads to the development of a serious phobic disorder: agoraphobia (agora means “open space”).

• Agoraphobia

• a fear of being away from home or other protected places

• Agoraphobia can be severely disabling; some people with this disorder have stayed inside their homes for years, afraid to venture outside where they might have a panic attack in public.

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Panic Disorder, Generalized Anxiety Disorder, and Social Anxiety Disorder

• The primary characteristics of generalized anxiety disorder are excessive anxiety and worry, difficulty in controlling these symptoms, and clinically significant signs of distress and disruption of their lives.

• Generalized Anxiety Disorder

• a disorder characterized by excessive anxiety and worry serious enough to cause disruption of their lives

• The prevalence of generalized anxiety disorder is approximately 3 percent, and the incidence is approximately 2 times greater in women than in men.

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Panic Disorder, Generalized Anxiety Disorder, and Social Anxiety Disorder

• Social anxiety disorder (also called social phobia) is a persistent, excessive fear of being exposed to the scrutiny of other people that leads to avoidance of social situations in which the person is called on to perform (such as speaking or performing in public).

• Social Anxiety Disorder

• a disorder characterized by excessive fear of being exposed to the scrutiny of other people that leads to avoidance of social situations in which the person is called on to perform

The prevalence of social anxiety disorder, which is equally likely in men and women, is approximately 5 percent.

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Treatment

• Anxiety disorders are sometimes treated with benzodiazepines.

• As we just saw, increased activity of the amygdala is a common feature of the anxiety disorders.

• The amygdala contains a high concentration of GABAA receptors, which are the target of the benzodiazepines.

• Paulus et al. (2005) found that administration of a benzodiazepine (lorazepam) decreased the activation of both the amygdala and the insula of subjects looking at emotional faces.

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Treatment

• Benzodiazepines are often used for emergency medical treatment for anxiety disorders because the therapeutic effects of these drugs have a rapid onset.

• However, they are less satisfactory for long-term treatment.

• They cause sedation, they induce tolerance and withdrawal symptoms, and they have a potential for abuse.

• For these reasons, researchers have been seeking other drugs to treat anxiety disorders.

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Much evidence suggests that serotonin plays a role in anxiety disorders too.

Figure 17.1 shows the effect of fluvoxamine, an SSRI, on the number of panic attacks in patients with panic disorder.

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Obsessive-Compulsive Disorder

• As the name implies, people with an obsessive-compulsive disorder (OCD) suffer from obsessions—thoughts that will not leave them—and compulsions—behaviors that they cannot keep from performing.

• Obsessive-Compulsive Disorder (OCD)

• a mental disorder characterized by obsessions and compulsions

• Obsession

• an unwanted thought or idea with which a person is preoccupied

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Obsessive-Compulsive Disorder

• Obsessions include concern or disgust with bodily secretions, dirt, germs, etc.; fear that something terrible might happen; and a need for symmetry, order, or exactness.

• Most compulsions fall into one of four categories: counting, checking, cleaning, and avoidance.

• Obsessions are seen in a variety of mental disorders, including schizophrenia.

• However, unlike schizophrenics, people with obsessive-compulsive disorder recognize that their thoughts and behaviors are senseless and desperately wish that they would go away.

Anxiety Disorders

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Obsessive-Compulsive Disorder

• Compulsion

• the feeling that one is obliged to perform a behavior, even if one prefers not to do so

• Compulsions often become more and more demanding until they interfere with people’s careers and daily lives.

• The incidence of obsessive-compulsive disorder is 1–2 percent.

• Females are slightly more likely than males to have this diagnosis. OCD most commonly begins in young adulthood (Robbins et al., 1984).

• People with severe symptoms this disorder are unlikely to marry, perhaps because of the common obsessional fear of dirt and contamination or because of the shame associated with the rituals they are compelled to perform, which causes them to avoid social contacts (Turner, Beidel, and Nathan, 1985).

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Obsessive-Compulsive Disorder

• Some investigators believe that the compulsive behaviors seen in OCD are forms of species-typical behaviors—for example, grooming, cleaning, and attention to sources of potential danger—that are released from normal control mechanisms by a brain dysfunction (Wise and Rapoport, 1988).

• Fiske and Haslam (1997) suggest that the behaviors seen in obsessive-compulsive disorder are simply pathological examples of a natural behavioral tendency to develop and practice social rituals.

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Possible Causes

• Tourette’s syndrome is characterized by muscular and vocal tics: facial grimaces, squatting, pacing, twirling, barking, sniffing, coughing, grunting, or repeating specific words (especially vulgarities).

• Tourette’s Syndrome

• a neurological disorder characterized by tics and involuntary vocalizations and sometimes by compulsive uttering of obscenities and repetition of the utterances of others

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Possible Causes

• A review by Saxena et al. (1998) described several studies that measured regional brain activity of OCD patients before and after successful treatment with drugs or cognitive behavior therapy.

• In general, the improvement in a patient’s symptoms was correlated with a reduction in the activity of the caudate nucleus and orbitofrontal cortex.

• The fact that cognitive behavior therapy and drug therapy produced similar results is especially remarkable: It indicates that very different procedures may bring about physiological changes that alleviate a serious mental disorder.

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Treatment

• As we saw in the prologue to this chapter, clinicians developed procedures that damaged the prefrontal cortex or disconnected it from other parts of the brain to treat people with emotional reactions.

• Some patients with severe OCD have been successfully treated with cingulotomy—surgical destruction of specific fiber bundles in the subcortical frontal lobe, including the cingulum bundle (which connects the prefrontal and cingulate cortex with the limbic cortex of the temporal lobe) and a region that contains fibers that connect the basal ganglia with the prefrontal cortex (Ballantine et al., 1987; Mindus, Rasmussen, and Lindquist, 1994).

• These operations have a reasonably good success rate (Dougherty et al., 2002).

• Another reasonably successful surgical procedure, capsulotomy, destroys a region of a fiber bundle (the internal capsule) that connects the caudate nucleus with the medial prefrontal cortex (Rück et al., 2008).

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Treatment

• Three drugs are regularly used to treat the symptoms of OCD: clomipramine, fluoxetine, and fluvoxamine.

• These effective antiobsessional drugs are specific blockers of 5-HT reuptake; thus, they are serotonergic agonists.

• In general, serotonin has an inhibitory effect on species-typical behaviors, which has tempted several investigators to speculate that these drugs alleviate the symptoms of obsessive-compulsive disorder by reducing the strength of innate tendencies for counting, checking, cleaning, and avoidance behaviors that may underlie this disorder.

Autistic Disorder

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Description

• When a baby is born, the parents normally expect to love and cherish the child and to be loved and cherished in return.

• Unfortunately, some infants are born with a disorder that impairs their ability to return their parents’ affection.

• The symptoms of autistic disorder (often simply referred to as autism) include a failure to develop normal social relations with other people, impaired development of communicative ability, and the presence of repetitive, stereotyped behavior. a chronic disorder whose symptoms include failure to develop normal social relations with other people, impaired development of communicative ability, lack of imaginative ability, and repetitive, stereotyped movements

• Most people with autistic disorder display cognitive impairments.

• The syndrome was named and characterized by Kanner (1943), who chose the term (auto, “self,”-ism, “condition”) to refer to the child’s apparent self-absorption.

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Description

• According to a review by Silverman et al. (2010), the incidence of autistic disorder is 0.6–1.0 percent in the population.

• The disorder is four times more common in males than in females.

• However, if only cases of autism with mental retardation are considered, the ratio falls to 2:1, and if only cases of high-functioning autism are considered (those with average or above-average intelligence and reasonably good communicative ability), the ratio rises to approximately 7:1 (Fombonne, 2005).

• These data suggest that the social impairments are much more common in males but the cognitive and communicative impairments are more evenly shared by males and females.

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Description

• Autistic disorder is one of several pervasive developmental disorders that have similar symptoms.

• Asperger’s syndrome, the mildest form of autistic spectrum disorder, is generally less severe than autistic disorder, and its symptoms do not include a delay in language development or the presence of important cognitive deficits.

• The primary symptoms of Asperger’s syndrome are deficient or absent social interactions and repetitive and stereotyped behaviors along with obsessional interest in narrow subjects.

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Description

• According to the DSM-IV, a diagnosis of autistic disorder requires the presence of three categories of symptoms: impaired social interactions, absent or deficient communicative abilities, and the presence of stereotyped behaviors.

• Social impairments are the first symptoms to emerge. Infants with autistic disorder do not seem to care whether they are held, or they may arch their backs when picked up, as if they do not want to be held.

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• They do not look or smile at their caregivers. If they are ill, hurt, or tired, they will not look to someone else for comfort.

• As they get older, they do not enter into social relationships with other children and avoid eye contact with them.

• In severe cases, autistic people do not even seem to recognize the existence of other people.

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Description

• The language development of people with autism is abnormal or even nonexistent.

• They often echo what is said to them, and they may refer to themselves as others do—in the second or third person.

• For example, they may say, “You want some milk?” to mean “I want some milk.”

• They may learn words and phrases by rote, but they fail to use them productively and creatively. Those who do acquire reasonably good language skills talk about their own preoccupations without regard for other people’s interests. They usually interpret other people’s speech literally.

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Description

• Autistic people generally show abnormal interests and behaviors.

• For example, they may show stereotyped movements, such as flapping their hand back and forth or rocking back and forth.

• They may become obsessed with investigating objects, sniffing them, feeling their texture, or moving them back and forth.

• They may become attached to a particular object and insist on carrying it around with them.

• They may become preoccupied in lining up objects or in forming patterns with them, oblivious to everything else that is going on around them.

• They often insist on following precise routines and may become violently upset when they are hindered from doing so.

• They show no make-believe play and are not interested in stories that involve fantasy.

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Heritability

• Evidence indicates that autism is strongly heritable.

• The best evidence for genetic factors comes from twin studies.

• These studies indicate that the concordance rate for autism in monozygotic twins is approximately 70 percent, while the rate in dizygotic twins studied so far is approximately 5 percent.

• The concordance rate for the more broadly defined autistic spectrum disorders (ASD), is 90 percent for monozygotic twins and 10 percent for dizygotic twins (Sebat et al., 2007).

• A study by Ozonoff et al. (2011) found that an infant with an older sibling with ASD has an 18.7 percent likelihood of developing an ASD.

• Having multiple older siblings with ASD increased the risk to 32.2 percent.

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Brain Pathology

• The fact that autism is highly heritable is presumptive evidence that the disorder is a result of structural or biochemical abnormalities in the brain.

• In addition, a variety of medical disorders—especially those that occur during prenatal development—can produce the symptoms of autism.

• Evidence suggests that approximately 10 percent of all cases of autism have definable biological causes, such as rubella (German measles) during pregnancy; prenatal thalidomide; encephalitis caused by the herpes virus; and tuberous sclerosis, a genetic disorder that causes the formation of benign tumors in many organs, including the brain (DeLong, 1999; Rapin, 1999; Fombonne, 2005).

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Brain Pathology

• Not all parts of the autistic brain show the same pattern of growth.

• The regions that appear to be most involved in the functions that are impaired in autism show the greatest growth early in life and the slowest growth between early childhood and adolescence.

• For example, the frontal cortex and temporal cortex of the autistic brain grow quickly during the first 2 years of life but then show little or no increase in size during the next 4 years, whereas these 2 regions grow by 20 percent and 17 percent, respectively, in normal brains.

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Brain Pathology

• Autistic brains also show abnormalities in white matter.

• Herbert et al. (2004) found that in the autistic brain, the volume of white matter containing short-range axons was increased but that the volume of white matter containing long-range axons that connect distant regions of the brain was not.

• Courchesne et al. (2005, 2007) suggest that the production of excessive numbers of neurons early in development may cause the development of such a large number of short-range axons that the development of long-range axons is inhibited.

• The apparent hyperconnectivity of local regions of the cerebral cortex might possibly account for the exceptional isolated talents and skills shown by some autistic persons.

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Brain Pathology

• Functional imaging during presentation of the animations showed normal activation of early levels of the visual association cortex (the extrastriate cortex), but activation of the superior temporal sulcus (STS) and the medial prefrontal cortex was much lower in members of the autism group. (See Figure 17.5)

• Previous research has shown that the STS plays an important role in detection of stimuli that indicate the actions of another individual (Allison, Puce, and McCarthy, 2000).

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Brain Pathology

• The lack of interest in or understanding of other people is reflected in the response of the autistic brain to the sight of the human face.

• As we saw in Chapter 6, the fusiform face area (FFA), located on a region of visual association cortex on the base of the brain, is involved in the recognition of individual faces.

• A functional-imaging study by Schultz (2005) found little or no activity in the fusiform face area of autistic adults looking at pictures of human faces. (See Figure 17.6.)

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Brain Pathology

• Research suggests that the same may be true for the behavioral symptoms of autism. Several studies have observed increased volume of the caudate nucleus in autism (Sears et al., 1999; Langen et al., 2007).

• In fact, Hollander et al. (2005) found that the volume of the right caudate nucleus was positively correlated with ratings of repetitive behavior in patients with ASD. (See Figure 17.7.)

Attention-Deficit/Hyperactivity Disorder

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• Some children have difficulty concentrating, remaining still, and working on a task.

• At one time or other, most children exhibit these characteristics.

• But children with attention-deficit/hyperactivity disorder (ADHD) display these symptoms so often that they interfere with the children’s ability to learn.

• Attention-Deficit/Hyperactivity Disorder (ADHD)

• a disorder characterized by uninhibited responses, lack of sustained attention, and hyperactivity; first shows itself in childhood

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Description

• ADHD is the most common behavior disorder that shows itself in childhood.

• It is usually first discovered in the classroom, where children are expected to sit quietly and pay attention to the teacher or work steadily on a project.

• Some children’s inability to meet these expectations then becomes evident.

• They have difficulty withholding a response, act without reflecting, often show reckless and impetuous behavior, and let interfering activities intrude into ongoing tasks.

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Description

• According to the DSM-IV, the diagnosis of ADHD requires the presence of six or more of nine symptoms of inattention and six or more of nine symptoms of hyperactivity and impulsivity that have persisted for at least six months.

• Symptoms of inattention include such things as “often had difficulty sustaining attention in tasks of play activities” or “is often easily distracted by extraneous stimuli,” and symptoms of hyperactivity and impulsivity include such things as “often runs about or climbs excessively in situations in which it is inappropriate” or “often interrupts or intrudes on others (e.g., butts into conversations or games)” (American Psychiatric Association, 1994, pp. 64–65).

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Description

• ADHD can be very disruptive of a child’s education and that of other children in the same classroom.

• It is seen in 4–5 percent of grade school children.

• Boys are about 10 times more likely than girls to receive a diagnosis of ADHD, but in adulthood the ratio is approximately 2 to 1, which suggests that many girls with this disorder fail to be diagnosed.

• Because the symptoms can vary—some children’s symptoms are primarily those of inattention, some are those of hyperactivity, and some show mixed symptoms—most investigators believe that this disorder has more than one cause.

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Description

• Adults with ADHD are also more likely to show cognitive impairments and lower occupational attainment than would be predicted by their education (Seidman et al., 1998).

• The most common treatment for ADHD is administration of methylphenidate (Ritalin), a drug that inhibits the reuptake of dopamine.

• Amphetamine, another dopamine agonist, also reduces the symptoms of ADHD, but this drug is used much less often.

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Attention-Deficit/Hyperactivity Disorder

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Possible Causes

• The symptoms of ADHD resemble those produced by damage to the prefrontal cortex: distractibility, forgetfulness, impulsivity, poor planning, and hyperactivity (Aron, Robbins, and Poldrack, 2004).

• As we saw in Chapter 13, the prefrontal cortex plays a critical role in short-term memory.

• We use short-term memory to remember what we have just perceived, to remember information that we have just recalled from long-term memory, and to process (“work on”) all of this information.

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Possible Causes

• Many studies have shown that the effect of dopamine levels in the prefrontal cortex on the functions of this region follow an inverted U-shaped curve. (See Figure 17.9.)

• Graphs of many behavioral functions have an inverted U shape.

• For example, moderate levels of motivation increase performance on most tasks, but very low levels fail to induce a person to perform, and very high levels tend to make people nervous and interfere with their performance.

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Possible Causes

• The dose-response curve for the effects of methylphenidate also follow an inverted U-shaped function, which is why Berridge and his colleagues tested different doses of the drug to find a dose that optimized the animals’ performance.

• Clinicians have found the same to be true for the treatment of ADHD: Doses that are too low are ineffective, and doses that are too high produce increases in activity level that disrupt children’s attention and cognition.

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• The word stress was borrowed from engineering, in which it refers to the action of physical forces of mechanical structures.

• The word can be a noun or a verb; the noun can refer to situations or the individual’s response to them.

• When we say that someone was subjected to stress, we really mean that someone was exposed to a situation that elicited a particular reaction in that person: a stress response.

• Stress Response

• a physiological reaction caused by the perception of aversive or threatening situations

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