What Is Abnormal

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Defining Psychological Disorders
FIGURE
12.1
21
Incidence of Specific
Psychological Disorders
15
Percentage
Several large-scale surveys of adults in the
United States revealed that about 30 percent of them experience some form of
mental disorder in any given year and that
almost half of them have displayed a disorder at some time in life. The data shown
here summarize these findings by category
of disorder. The same general patterns appear among the more than 400 million
people worldwide who suffer from some
form of psychological disorder (Andrade
et al., 2002; Bjil et al., 2003; Liu et al.,
2002; World Health Organization, 2002b;
World Health Organization Mental Health
Survey Consortium, 2004).
18
12
9
6
3
Substancerelated
disorders
Anxiety
disorders
Mood
disorders
Antisocial
personality
disorder
Schizophrenia
and related
disorders
2005; Narrow et al., 2002; see Figure 12.1). In addition, about 20 percent of U.S. children display significant mental disorder in any given year (Costello et al., 2003; U.S.
Surgeon General, 1999). These rates of mental disorder have remained steady in recent
years and are seen in all segments of U.S. society. As described later, though, some disorders are more prevalent in males or females or in certain ethnic groups (Beals et al.,
2005; Peterson et al., 1993). The overall prevalence rates may actually be higher than
the survey percentages suggest, because major studies have examined fewer than half
of all known psychological disorders. In short, psychological disorders are enormously
costly in terms of human suffering, wasted potential, economic burden, and lost
resources (Druss, Rosenheck, & Sledge, 2000; Lyons & McLoughlin, 2001; Marcotte &
Wilcox-Goek, 2001; Stewart et al., 2003).
Defining Psychological Disorders
䉴 How do psychologists define abnormal behavior?
A woman’s husband dies. In her grief, she stays in bed all day, weeping, refusing to eat,
at times holding “conversations” with him. In India, a Hindu holy man on a pilgrimage rolls along the ground for more than 1,000 miles of deserts and mountains, in all
kinds of weather, until he reaches the sacred place he seeks. A British artist randomly
scratches parked cars as part of his “creative process” (Telegraph Correspondent, 2005).
Eight percent of U.S. adults surveyed say they have seen a UFO (CNN/Time, 1997),
and hundreds claim to have been abducted by space aliens (Appelle, Lynn, & Newman,
2000). These examples and countless others raise the question of where to draw the
line between normality and abnormality, between eccentricity and mental disorder
(Kanner, 1995).
What Is Abnormal?
There are several criteria for judging whether a person’s thinking, emotions, or behaviors are abnormal. Each criterion has value but also some flaws.
If we define normality as what most people do, then the criterion for abnormality
becomes statistical infrequency, or that which is unusual or rare. By this criterion, the
few people who believe that space aliens steal their thoughts would be judged as abnormal; the many people who worry about becoming victims of crime or terrorism would