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).