Anxiety disorders

Author : Richard J. McNally Professor and Director of Clinical Training, Department of Psychology, Harvard University

2008-04-16

What Are Anxiety Disorders?

Anxiety disorders are characterized by intense fear and anxiety, and by attempts to avoid activities and situations that trigger these emotional states [1]. The occurrence of fear and anxiety per se do not indicate the presence of an anxiety disorder. Indeed, these are normal emotions that likely fostered survival throughout the course of evolution, and hence are often adaptive [2]. Fear is triggered by an immediate threat, and it mobilizes the person to fight or flee. Anxiety is triggered by the prospect of future threat, and it can motivate a person to take steps to prevent the threat from materializing.

If anxiety and fear are adaptive emotions, when do they become anxiety disorders? Although the border between normal and abnormal anxiety is fuzzy, there are guidelines for identifying when anxiety is pathological. First, the fear or anxiety is disproportionate to the actual threat. That is, the person either overestimates the likelihood of the feared event occurring or exaggerates how bad it would be if it did occur, or both. For example, a person with obsessive-compulsive disorder may fearfully avoid touching a public toilet seat because of concern about contracting AIDS. Yet the actual likelihood of this catastrophe coming to pass is vanishingly small. Or a person with social phobia may dread speaking in public because of concern that others will notice her trembling hands or quavering voice. But even if her nervousness were visible to the audience, it would not constitute the catastrophe she envisions it to be. Hence, anxiety (or fear) is disproportionate or excessive when the person either overestimates the probability of the event, exaggerates its negative valence (its “badness”), or both.

But even if a person’s fear and anxiety is disproportionate to the actual threat, he or she still does not qualify for an anxiety disorder. Other criteria must still be met. The fear, anxiety, and avoidance of threat must be persistent, and it must either cause significant distress for the person, impair his or her functioning in everyday activities, or both. For example, a man might have an intense fear of driving in the snow because of concern about losing control of the car and crashing. This persistent fear could greatly interfere with his life as long as he lives in snowy upstate New York, thereby qualifying him for specific phobia of driving. But he would no longer qualify for this anxiety disorder if he moved to Miami. He would no longer be living in dread of the next snowfall, and his fear of driving in snow would no longer have an adverse impact on his daily life.

In summary, for a person to qualify as having an anxiety disorder, his or her fear and anxiety must be disproportionate, persistent, and cause significant distress or impairment in everyday life.

What Are the Types of Anxiety Disorder?

All anxiety disorders involve persistent, disproportionate, impairing fear and anxiety. Yet these features can manifest in different ways, as embodied in the different types of anxiety disorder. It is not uncommon for a person to have more than one anxiety disorder at a time, and many people with anxiety disorders suffer from depression as well.

Panic Disorder and Agoraphobia

Panic disorder is characterized by panic attacks: episodes of terror that seemingly “come out of the blue” and that do not seem triggered by any obvious external stimulus [3, 4]. Panic attacks occur abruptly, and reach peak intensity within minutes.

Panic attacks are marked by intense physiological symptoms including dyspnea (difficulty breathing and feelings of suffocation), a pounding or rapid heart rate, dizziness, faintness, feeling disconnected from one’s body (depersonalization), or one’s environment (derealization), nausea, hot or cold flashes, paresthesias (tingling sensations, often in the hands or face), and thoughts that one is about to faint, die from a heart attack or stroke, or “go crazy.” In reality, panic does not directly cause heart attacks or insanity, and it is extremely unusual for a person to faint during an attack. Indeed, the unrealistic fear of these disastrous outcomes seems to fuel the fear of panic.

Panic attacks do not last very long. Most wane within minutes, leaving the person shaken and emotionally drained. Yet, if panic attacks persist, the person may begin to live in dread of the next attack, and begin to avoid places where escape might be difficult should panic strike again. Although the onset of panic disorder is usually marked by the occurrence of unexpected, uncued, seemingly “spontaneous” attacks, after awhile the person may notice that the attacks are more likely to occur in some situations than in others. These situations can provide the occasion for cued panic attacks. For example, people may experience anticipatory anxiety about entering shopping malls, driving on crowded expressways, using an elevator, going to movies or concerts, attending church, flying on airplanes, or traveling alone, unaccompanied by a family member or trusted friend. Anxiety in these situations, all of which are difficult to escape gracefully should panic strike, may produce symptoms that further frighten the person. In other words, fear of anxiety-related symptoms may worsen the symptoms, producing a vicious circle that culminates in panic. If widespread avoidance of activities and situations develops, then a diagnosis of panic disorder with agoraphobia is warranted. In the most severe cases, a person may become housebound because of fear of panicking away from home. Some people will awaken from sleep in the midst of a panic attack.

Contrary to what many people think, agoraphobia is not a fear of open spaces per se. Rather, it is a fear of panicking in places where escape would be difficult. In fact, some clinicians refer to panic disorder with or without agoraphobia as a “fear of fear” itself [5]. Studies suggest that anxiety sensitivity [6, 7] – the preexisting tendency to fear symptoms related to anxiety – increases the likelihood that people will respond fearfully to certain bodily sensations, thereby leading to panic attacks. Some people may misinterpret these sensations (e.g., heart palpitations) as signifying an impending catastrophe (e.g., heart attack), thereby worsening their fear so that it spirals upward into panic [8]. Occasionally, people will develop agoraphobic avoidance without first having had full-blown panic attacks. Yet even in these cases the avoidance is motivated by fear of being stricken by some bodily reactions (e.g., diarrhea, migraine headache) away from home. Some people with panic disorder never develop avoidance of public places, and hence only meet criteria for panic disorder without agoraphobia. Nevertheless, they may avoid doing certain things that might trigger the dreaded bodily sensations, such as consuming caffeinated beverages.

Panic attacks often begin during a period of life stress (e.g., marital problems, death of a relative, going away to college), and there appear to be two peak ages of onset: late adolescence and the mid-30s. It is rare for prepubertal children to experience panic attacks, and panic seldom begins in late life. It has a waxing and waning course, but can be chronic if the person fails to get proper treatment.

Persistent panic attacks, including unexpected, uncued ones, and persistent dread of further attacks coupled with behavioral change, including avoidance behavior, is what constitutes panic disorder. About 4.7% of the American population has had panic disorder at some point in their lives (lifetime prevalence) [9], and about 2.7% has had panic disorder during the previous year (annual prevalence) [10]. People with other mental disorders, such as depression, can also experience panic attacks, as can people in the general population. But an isolated panic attack unaccompanied by a persistent fear of further attacks does not constitute panic disorder.

Social Phobia (Social Anxiety Disorder)

People with social phobia fear and avoid situations or activities where they may experience embarrassment, humiliation, or negative evaluation by others. Fearing that others will regard them as nervous, weak, and incompetent, they almost invariably experience intense symptoms of anxiety whenever they are about to encounter a social evaluative situation. Common symptoms include blushing, trembling, sweating, nausea, and feeling tongue-tied and inarticulate. Their acute self-consciousness about others’ noticing these symptoms only tends to make them worse, setting up a vicious circle.

The focus of concern in social phobia is negative evaluation by other people. Any situation that may prompt critical scrutiny by others can be very difficult for the person with social phobia. So, for example, many people with this disorder avoid doing things in front of others, such as eating, drinking, or signing checks. They fear that others will notice that their hands are trembling, and will regard them with scorn because of their public display of anxiety symptoms.

Although a minority of people with this disorder fear and avoid only circumscribed situations, such as public speaking, others experience intense anxiety in a wide range of social interactional contexts, such as asking someone out for a date, engaging in conversation, attending parties, meeting strangers, and speaking to authority figures. People with this generalized form of social phobia may have deficits in social skills and experience awkwardness and uncertainty about what to say and do in an interpersonal context.

Social phobia is not mere shyness [11]. People with this disorder experience impairment in their personal, academic, and occupational lives. The more social situations that a person fears, the more likely he or she will experience problems in daily life. The peak age of onset is in early adolescence, although some people report having been extremely shy for as long as they can remember. Unless treated, the disorder may persist for decades. About 12.1% of American adults have had social phobia at some point during their lives [9], whereas about 6.8% have had the disorder during the previous year [10]. Longing to connect with other people, but fearful of rejection, individuals with this disorder can suffer from aching loneliness and may develop depression, other anxiety disorders, and problems with substance abuse.

Specific Phobia

Specific phobias are the most common anxiety disorders in the general population. About 12.5% of people have specific phobia at some point in their lives [9], and about 8.7% have had the disorder in the previous year [10]. Many people with this problem either manage to avoid their feared situation, or endure it with distress. Only when matters become intolerable do they seek treatment. There are several distinct subtypes of specific phobia [1].

Specific fears of snakes, spiders, and heights are very common in the general population. But such a fear only counts as a specific phobia if it is intense, persistent, and disproportionate, and it results in either marked distress, impairment in everyday life, or both. Adolescents and adults with specific phobia realize that their fear is excessive, but young children may not. An encounter with the phobic object or situation almost always triggers a very intense fear reaction.

Researchers have discerned several subtypes of specific phobia. The animal subtype is very common in the general population, but much less so in the clinic. Under this rubric are phobias of spiders, mice, insects, dogs, birds, cats, and snakes. People with animal phobia usually report that they have feared the animal for as long as they can remember, thereby implying an early childhood onset. Although in rare instances the person might have had an actual painful encounter with the animal (e.g., being bitten by a dog as a child), this is usually not the case. More often, the person recalls having experienced inexplicable terror upon encountering the creature early in childhood.

Some people with animal phobia fear being harmed, whereas others realize that no danger is present yet nevertheless experience intense fear. They also experience the emotion of disgust at the prospect of coming into contact with snakes, cockroaches, and spiders.

The natural environment subtype comprises fears of a diversity of settings, including heights (the most common), thunderstorms, or water. In some cases, the person dreads the physical consequences of encountering the feared situation, such as falling to one’s death from a high place, being struck by lightning, or drowning in a lake. In other cases, the person avoids the situation because it so reliably incites terror, and the experience of intense fear itself is highly distressing and therefore motivates avoidance. For example, people with height phobia (acrophobia) often dread peering out of floor-to-ceiling windows in high-rise apartments, not because they believe they might fall through the window, but because they dread experiencing the intense fear automatically provoked by the visual perception of height.

Natural environment phobias usually have a childhood onset, and height phobia is an extreme version of an adaptive wariness of heights that emerges shortly after children begin to crawl. Early humans who lacked this wariness would have been at increased risk for early death, whereas their more wary peers would have been more likely to survive and reproduce. Unlike most people with specific phobias, those with acrophobia tend to freeze in place, rather than abruptly flee the feared situation.

The blood-injection-injury subtype is common in the clinic as well as in the community. It differs in several important ways from other phobias. People with this problem often faint in the presence of blood-related stimuli, and hence their fear and avoidance of these stimuli has a rational basis even though it may cause impairment in everyday life. In striking contrast to people with other anxiety disorders, those with blood phobia experience a sudden drop in blood pressure and heart rate (after first experiencing a brief increase) upon encountering their feared stimuli. It is the sudden drop in blood pressure that triggers the fainting response.

Having blood drawn is the classic phobic situation for people with this problem. Other situations include receiving injections, having dental work done, seeing a child’s bloody nose, and watching a gruesome movie. This fear can be impairing because it can interfere with medical and dental treatment, and it can produce difficulty for those seeking to earn a living in health care as a nurse or physician. Blood phobia usually begins in childhood.

The situational subtype includes a miscellaneous group of phobias. Among the most common is a fear of enclosed spaces, or claustrophobia. People with this problem fear and avoid situations where they feel trapped and worry that they may be unable to breathe. Individuals with claustrophobia suffer in a variety of situations, including riding in elevators, being in a small room without windows, riding in the back seat of a small automobile, taking the subway, sitting in a crowded theater, or wearing a mask (e.g., gas mask in the military; snorkeling). The focus of concern for many claustrophobic people is experiencing a panic attack in a place where they cannot gracefully exit. Accordingly, distinguishing between claustrophobia and panic disorder with agoraphobia can be difficult. A diagnosis of claustrophobia would be warranted if the person only panics in enclosed spaces.

Another common situational phobia is fear of flying in airplanes. Once again, people with claustrophobia and panic disorder with agoraphobia may dread this form of travel. After all, being enclosed in an airplane is about as “trapped” as one can get. But most people with a specific phobia of flying dread crashing, not entrapment per se [12]. Many have had rocky flights or have been exposed to news coverage of plane crashes. They become attuned to turbulence or other sounds on the aircraft which they fear may prefigure malfunction and possible crash.

Situational phobias have two peak ages of onset. Some people begin suffering from these fears in childhood, whereas others begin suffering from them in their early 20s. In the latter group, a sudden panic attack in the to-be-feared situation may signal the onset of subsequent fear and avoidance of the situation.

Finally, there is a miscellaneous group of phobias that do not fit easily into any of the aforementioned categories. Some people develop a fear of eating solid food or swallowing pills, usually after having nearly choked on food. Impairment can be marked, especially when a person’s fear limits food intake to foods such as yogurt.

Other people develop an intense fear of vomiting or witnessing another person vomiting. Some phobias can be unusual, such as fears of clowns, dolls, mannequins, or balloons popping. Finally, a rare problem, called space phobia, is characterized by a fear of falling in the absence of support. Unlike other phobias, this one emerges in middle or old age, and may arise from neurological dysfunction.

Some theorists believe that certain specific phobias, such as those of snakes, heights, and blood, are exaggerations of otherwise adaptive fears. According to this view, our ancestors who tended to fear these stimuli tended to survive and reproduce more often than those who were more fearless [13]. A related view holds that certain stimulus characteristics, such as discrepancy from the human form or a tendency to move quickly and unpredictably, may be hard-wired to provoke wariness and fear in human beings.

Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is characterized by recurrent thoughts, images, or impulses that increase anxiety, fear, or distress. Most typically, the person recognizes that the obsessions are absurd, repugnant, and unrealistic. The most common obsessions concern contamination (e.g., coming into contact with germs by touching a doorknob, contracting AIDS by touching a toilet seat), doubt (e.g., thinking one may either have failed to perform an important action, such as locking the door or turning off the gas on the stove before leaving the house, or thinking one may have performed a terrible action, such as running over a pedestrian while driving one’s car), symmetry (e.g., concern that the pictures on the wall are tilted or that certain objects are arranged in a perfectly organized manner), aggressive impulses or images (e.g., concern that one may butcher one’s infant with a knife), blasphemy (e.g., feeling that one is about to blurt out obscenities in church), or sex (e.g., recurrent images of repugnant sexual acts). Although people with OCD recognize that the obsessions are the product of their minds and not inserted by some alien force, as psychotic individuals may believe, they nevertheless regard them as ego-dystonic or alien to their personality. Obsessions are distressing and unwanted, and hence a person craving the pleasure of smoking a cigarette, or a lover preoccupied with the beloved are not experiencing obsessions. Obsessions are also not about realistic worry such as repeated distressing thoughts about how one can pay one’s bills.

Obsessions are experienced as involuntary, whereas compulsions are experienced as at least partly voluntary. Compulsions are thoughts or actions performed by the person to reduce the distress associated with an obsession, to prevent a feared disaster from occurring, or both. So, people with contamination obsessions repeatedly wash their hands. People with doubting obsessions will repeatedly check to confirm that the door is really locked and the gas taps turned off, or will repeatedly retrace one’s driving route to make sure that they have not run over a pedestrian by accident. People with symmetry obsessions may engage in compulsive ordering rituals to ensure that everything is arranged just so. Those with harming obsessions may think certain thoughts that “neutralize” the threatening thought, and these cognitive rituals have the same anxiety-reducing function as do behavioral rituals such as washing and checking.

OCD often begins in childhood, especially for boys, and it can have a chronic course if left untreated. People with OCD are at risk for depression, and some individuals will also have tics as well. About 1.8% of the population develops OCD during their lives [9], and about 1.1% has had OCD during the previous year [10].

Generalized Anxiety Disorder

People with generalized anxiety disorder (GAD) suffer from excessive and unrealistic worry about at least several different matters. To qualify for the diagnosis, they must have experienced anxiety and worry on more days than not for at least six months, and they must have at least three of the following symptoms: feeling on edge, keyed up, or restless; becoming easily fatigued; having difficulty concentrating or having one’s mind go blank; irritability; tense muscles; and having difficulty either falling asleep or staying asleep, or failing to be rested after having slept. Finally, they must find it difficult to control their worry.

Although many people with other anxiety disorders also qualify for GAD, for a diagnosis of GAD to be warranted, the person’s worry must not be confined to the central concern of another disorder (e.g., being embarrassed in social phobia; having a panic attack; being contaminated in OCD). The kinds of concerns that trouble people with GAD are often similar to those of other people (e.g., relationships, jobs, children, finances). However, in GAD the anxious expectation of harm is disproportionate to the likelihood of the threat materializing, and worry is very difficult to control.

Many people with GAD say that they have always been worriers, and more than half of patients with the disorder date its onset to childhood or adolescence. Some patients, however, say that their GAD began only in adulthood. The severity of GAD can wax and wane, and can be chronic. About 2.7% of the general population will qualify for GAD during the previous year [9], and about 5.7% of the general population will develop GAD at some point in their lives [10].

Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) can occur in people exposed to terrifying, often life-threatening events, such as combat, violent assaults, including rape, and natural disasters [14]. Some people may develop PTSD after witnessing others exposed to these traumas. To be diagnosable with PTSD, a person must be exposed to a traumatic event, and must have reacted with fear, horror, or helplessness during the trauma.

Unlike the other anxiety disorders where the focus of concern is a threat lying in the future, PTSD concerns a threat that lies in the past, but intrudes in the present. People with PTSD behave as if danger were current rather than something in the past.

PTSD is a disorder of memory [15]. That is, the person exposed to a trauma encodes a memory of the event, and this memory gives rise to the symptoms of the disorder. The symptoms are grouped in three clusters. The reexperiencing cluster includes intrusive, distressing thoughts about the trauma; trauma-related nightmares; increased distress and physiological reactivity (e.g., increased heart rate) upon encounters with reminders of the trauma, and “flashback” experiences – recollections so vivid that it seems as if the event were occurring all over again.

The second cluster comprises the avoidance and numbing symptoms. People with PTSD do not relish being haunted by their memories of trauma, and so they endeavor to avoid reminders of their terrible experience. For example, war veterans may avoid talking about combat, or rape victims may avoid wearing clothes they had on during the assault. Some individuals with PTSD may feel as if their future is foreshortened, and that the hazardous unpredictability of life precludes them from envisioning how their lives will unfold months or years later. People with PTSD may experience emotional numbing characterized by difficulty experiencing positive feelings toward others and by difficulty enjoying previously pleasurable activities.

The third cluster comprises symptoms of heightened arousal. These include irritability, exaggerated startle reactions, difficulty concentrating, and problems falling or staying asleep.

In the immediate wake of trauma, many people experience difficulty sleeping, intrusive thoughts, and so forth. But these symptoms usually wane within days or weeks. PTSD cannot be diagnosed unless symptoms have persisted for at least one month, and symptoms must produce either significant distress, impairment, or both. In rare circumstances, a person may develop PTSD months or years after the trauma. Yet even in these cases the person almost always had at least some symptoms in the immediate wake of the trauma, and only later developed additional symptoms to qualify for the disorder.

Most people exposed to traumatic events do not develop PTSD. Accordingly, researchers have identified variables that either increase or decrease risk for PTSD among those exposed to trauma. Elevated neuroticism – a personality trait associated with anxiety, anger, sadness, and guilt – is associated with risk for PTSD, as is either a personal or family history of mood or anxiety disorders. People with above average intelligence are less likely to develop PTSD relative to those with average or below-average intelligence.

Finally, women are about twice as likely to develop PTSD as are men, even though men are more often exposed to trauma than women.

Only about 10-20% of people exposed to traumatic events develop PTSD. Exposure to violent assault, including combat and rape, leads to PTSD more often than does exposure to other events (e.g., car accidents). About 6.8% of Americans will develop PTSD at some point in their lives [9], and about 3.5% qualify for the disorder during the previous year [10].

Acute Stress Disorder

Acute stress disorder (ASD) is a PTSD-like syndrome diagnosable in people within one month following their exposure to a traumatic event. In many ways, ASD is really an acute form of PTSD except that certain dissociative symptoms must occur either during the trauma or within one month following the trauma. These include feelings of unreality, being in a daze, a lack of emotional responsiveness, and depersonalization. Clinicians originally believed that these dissociative symptoms were especially predictive of later PTSD, but this apparently is not the case. To the extent that ASD predicts later PTSD, this is driven by the overlap of PTSD-like symptoms between the two disorders. Therefore, ASD may be an early form of PTSD rather than a distinct disorder in its own right [16].

 

Treatment of Anxiety Disorders

The main approaches to treating anxiety disorders are cognitive-behavior therapy (CBT) and pharmacotherapy [17, 18]. The exposure principle is the main guideline for CBT for anxiety disorders. According to this principle, the best way of treating excessive, unwarranted fear is to have patients expose themselves to feared situations until their fear diminishes. There are two main forms of exposure therapy, in vivo (real-life) exposure and imaginal exposure. Most therapists favor graduated in vivo exposure to feared stimuli. For example, a person who fears heights will be asked to walk up a fire escape, stopping at each landing and peering downward until subjective distress diminishes, and then walking up the next flight of stairs, reaching the next landing, and again peering downward until fear wanes. The person gains a sense of mastery over the phobia as the fear reactions decline. The exposure principle is based on the insight that repeated contact with fear-evoking, but objectively harmless, situations decreases the intensity of fear.

      Therapists adapt the exposure principle to the nature of the fear. Patients who fear snakes, spiders, or other harmless creatures will first approach the animal from a distance and eventually move closer and handle the animal itself. Patients with social phobia will practice engaging in progressively more challenging social interactions, and patients with panic disorder and agoraphobia will undergo both interoceptive exposure and in vivo exposure to avoided situations (e.g., shopping malls, driving). Interoceptive exposure involves deliberate provocation of feared bodily sensations until distress wanes. So, for example, a therapist may have a patient hyperventilate, spin in a chair, breathe through a straw, or run up a flight of stairs in order to produce lightheadedness, dizziness, difficulty breathing, and pounding heart – all feared bodily sensations.

Patients with blood phobia learn first to tense the muscles in their legs and buttocks to ensure that their heart rate and blood pressure remain at least at normal levels, and these “applied tension” exercises are done while patients confront increasingly more threatening blood-related stimuli. Exposure, coupled with applied tension, ensures that distress diminishes and that the patient does not faint during exposure.

Treatment of PTSD involves structured imaginal exposure to memories of the trauma. Patients are asked to close their eyes, imagine, and recount aloud the trauma in the first person, present tense. By confronting, rather than avoiding, the memory, the patient’s anxiety diminishes. Imaginal exposure is akin to watching a frightening movie again and again. Eventually it loses its power to frighten. Many PTSD patients avoid reminders of the trauma, and therapists encourage them to expose themselves to these reminders (e.g., begin driving an automobile again for those whose PTSD resulted from a car crash).

The standard treatment for OCD involves exposure to obsession-triggering stimuli coupled with response prevention (refraining from performing compulsive rituals). So, the person may touch “contaminated” items (e.g., doorknobs, dollar bills, toilet seats, trash cans) without washing afterward, or may turn gas taps on and off, or lock doors, and so forth without rechecking to ensure that it was done correctly. By refraining from washing, checking, or performing other compulsive rituals, the patient learns that his or her anxiety diminishes naturally.

          Therapists identify and target cognitive distortions, such as exaggerated estimates of threat and negative valence. Patients learn to consider their feared beliefs as hypotheses to be tested by gathering evidence bearing on them and by engaging in behavioral experiments. For example, a patient with panic disorder who believes that she may collapse if she gets dizzy may be asked to spin in a chair, and then stand up. The fact that she can endure these sensations without collapsing reduces her fear of them, and refutes the hypothesis that she will collapse upon standing up. Patients with GAD whose excessive worries often arise from distorted beliefs can likewise benefit from cognitive interventions.

Selective serotonin reuptake inhibitors (SSRIs) can benefit a range of anxiety disorders, including OCD, social phobia, PTSD, GAD, and panic disorder. They are seldom useful for specific phobias. The efficacy of these drugs is about the same as CBT. Relapse, however, is often more likely for people once they terminate medication relative to people who have had CBT. Adding CBT to medication prior to medication withdrawal can reduce the chance of relapse. Combined drug plus CBT is seldom more effective than CBT alone.

Web links

Anxiety Disorders Association of America: www.adaa.org

Obsessive Compulsive Foundation: www.ocfoundation.org/what-is-ocd.html

References

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