254 CHAPTER 7
had their symptoms arise at a younger age (Moffi tt et al., 2007), to have more severe
symptoms of each disorder, and to function less well than those who have only one of
the two disorders (Zimmerman & Chelminski, 2003). Among people over 50 years
old—the age group in which GAD is most common—depression often arises after
GAD (Lenze et al., 2005; Schoevers et al., 2005). The high comorbidity also suggests
that GAD and depression may refl ect different facets of the same underlying problem,
which is rooted in distress, worry, and rumination (Schoevers et al., 2003).Understanding Generalized Anxiety Disorder
GAD can be best understood by using the neuropsychosocial approach to examine
its etiology—by considering neurological, psychological, and social factors and the
feedback loops among them. Each type of factor, by itself, seems to be necessary but
not suffi cient to give rise to this disorder. Neurological and psychological factors set
the stage, and social factors can trigger the symptoms.Neurological Factors
Let’s examine the role of neurological factors in GAD. We’ll see that the right hemi-
sphere of the brain appears to play a special role in GAD, that a complex mix of
neurotransmitters is involved in the disorder (largely by affecting the autonomic
nervous system and brain areas involved in registering reward), and that genetics
sets the stage by predisposing someone to develop GAD.Table 7.2 • Generalized Anxiety Disorder Facts at a Glance
Prevalence- Approximately 5% of people will develop GAD in their lifetime, with women over age 40 at
highest risk (approximately 10% of this group will develop the disorder) (American Psychiatric
Association, 2000; Kessler et al., 2005; Somers et al., 2006). - Primary care physicians report that their patients suffer from GAD more frequently than other
anxiety disorders (Lieb, Becker, & Altamura, 2005; Wittchen & Hoyer, 2001).
Comorbidity- GAD occurs very frequently with depression, with up to 80% of those having GAD during their
lives also experiencing depression at some point ( Judd et al., 1998). - Approximately half of the people who have both GAD and depression during their lifetimes
have both disorders at the same time (Ansseau et al., 2005).
Onset- Approximately half the people with GAD develop the disorder between the ages of 10 and 19,
whereas most others, particularly women, develop it sometime after turning 40 (Hoehn-Saric,
Hazlett, & McLeod, 1993; Wittchen & Hoyer, 2001).
Course- Once someone has GAD, its course is likely to be chronic, with symptoms fl uctuating in
response to stress.
Gender Differences- Twice as many women as men are diagnosed with GAD.
Cultural Differences- The content of the worries of people with GAD is shaped by their culture, their personal
experiences, and the environment in which they live. Some people worry about catastrophic
events, such as natural disasters; others worry about human-caused calamities, such as
nuclear war or terrorist acts.
Source: Unless otherwise noted, the source for information is American Psychiatric Association, 2000.