Causes of Anxiety Disorders
468 Chapter 12 Psychological Disorders panic attacks that may lead to agoraphobia as the person begins to fear and avoid places in which help won’t be available should panic recur (Carter & Barlow, 1995; Kessler et al., 2006). Panic disorder may last for many years, with periods of improvement followed by recurrence (Ehlers, 1995). As many as 30 percent of the U.S. population have experienced at least one panic attack within the past year, but full-blown panic disorder is seen in only about 1 to 2 percent of the population in any given year (American Psychiatric Association, 2000; Kessler, Chiu, et al., 2006; U.S. Surgeon General, 1999). Here is one example: Geri, a thirty-two-year-old nurse, had her ﬁrst panic attack while driving on a freeway. Afterward, she would not drive on freeways. Her next attack occurred while with a patient and a doctor in a small examining room. A sense of impending doom ﬂooded over her, and she burst out of the ofﬁce and into the parking lot, where she felt immediate relief. From then on, fear of another attack made it impossible for her to tolerate any close quarters, including crowded shopping malls. She eventually quit her job because of terror of the examining rooms. Obsessive-Compulsive Disorder Anxiety is also at the root of obsessivecompulsive disorder (OCD), which affects about 2.4 percent of the U.S. population A CLEANING COMPULSION Obsessivecompulsive disorder is diagnosed when a culturally expected degree of cleanliness turns into an obsessive preoccupation with germs and a life-disrupting compulsion to clean things. Learning and stress appear to play the major role in shaping and triggering this and other anxiety disorders, but biological factors, including genetically inherited characteristics and problems in certain neurotransmitter systems, may result in an oversensitive nervous system and a predisposition toward anxiety. in any given year (American Psychiatric Association, 2000; Howarth & Weissman, 2000; U.S. Surgeon General, 1999). People displaying this disorder are plagued by persistent, upsetting, and unwanted thoughts—called obsessions—that often focus on the possibility of infection, contamination, or doing harm to themselves or others. They don’t actually carry out harmful acts, but the obsessive thoughts motivate repetitive behaviors—called compulsions—that the person believes will prevent infection, aggressive acts, or other events associated with the obsessions (Foa & Kozak, 1995). Common compulsions include rituals such as checking locks; repeating words, images, or numbers; counting things; or arranging objects “just so.” Obsessions and compulsions are much more intense than the familiar experience of having a thought or tune running “in the back of your mind” or rechecking a door to see that it is locked. In OCD, the obsessions and compulsions are intense, disturbing, and often strange intrusions that can severely impair daily activities. (DSM-IV deﬁnes compulsions as taking up more than one hour a day.) Many of those who display OCD recognize that their thoughts and actions are irrational, but they still experience severe anxiety if they try to interrupt their obsessions or give up their compulsive rituals. Causes of Anxiety Disorders As with all the forms of psychopathology we consider, the exact causes of anxiety disorders are a matter of some debate. However, there is good evidence that biological, psychological, and social factors all contribute. Biological predispositions, distortions in thinking, and certain learning experiences appear to be particularly important causal factors (U.S. Surgeon General, 1999). obsessive-compulsive disorder (OCD) An anxiety disorder in which a person becomes obsessed with certain thoughts or feels a compulsion to do certain things. Biological Factors Most anxiety disorders appear to run in families (Kendler et al., 1995, 2001; Pauls et al., 1995; Skre et al., 2000; Wittchen et al., 1994), suggesting that these disorders are inﬂuenced by a genetic predisposition (Hettema et al., 2003, 2005; Maron et al., 2005). For example, if one identical twin suffers an anxiety disorder, the other is more likely to share that disorder than is the case in nonidentical twin pairs (e.g., Hettema, Neale, & Kendler, 2001; Kendler et al., 1992, 2002; Neumeister et al., 2004). What is actually inherited? Anxiety disorders might stem from a tendency to react with anxiety to a wide range of situations, and this tendency, in turn, might result partly from inheriting an autonomic nervous system that is oversensitive to stress (Ahmad et al., 2002; Hamilton et al., 2003; Zinbarg & Barlow, 1996). There may be more speciﬁc predispositions as well. One study found that identical twins were more likely than other siblings to share phobias of small animals and social situations but not of heights or enclosed spaces (Skre et al., 2000).