Cognitive Therapy of Anxiety Disorders

Generalized Anxiety Disorder 395

Clinician Guideline 10.4

Chronic and excessive worry is an important characteristic of GAD and its vulnerability. It is

a self- perpetuating maladaptive cognitive avoidance strategy that contributes to the persis-

tence of anxiety by (1) magnifying a biased interpretation of anticipated threat; (2) generat-

ing a false sense of control, predictability, and certainty; (3) ensuring erroneous attribution

of the nonoccurrence of the dreaded outcome to the worry process; and (4) culminating in

frustrative attempts to establish a sense of safety.

epiDemiology anD ClinCial features

Prevalence

In the NCS epidemiological study DSM-III-R GAD had a 12-month prevalence of 3.1%
and a lifetime prevalence of 5.1% (Kessler et al., 1994). Similar prevalence figures (3.1%
for 12 month; 5.7% for lifetime) were recently reported in the NCS-R that was based
on DSM-IV diagnostic criteria for GAD (Kessler, Berglund, et al., 2005; Kessler, Chiu,
et al., 2005). The prevalence rates for GAD vary considerably across different countries
(Holaway, Rodebaugh, & Heimberg, 2006). It is difficult to know whether this reflects
cross- national differences in rates of GAD or methodological variations in diagnostic
criteria and interview measures. Some of the older studies were based on DSM-III crite-
ria whereas more recent studies utilized DSM-III-R or DSM-IV.
Higher rates of GAD have been found in primary care settings. For example, Olfson
et al. (2000) reported a current prevalence of 14.8% in a large urban general practice,
making GAD the most prevalent anxiety disorder in this setting. In the NCS-R GAD was
second to panic disorder in the 12-month prevalence rates for use of general medical ser-
vices and similar to social phobia in the use of mental health specialties (Wang, Lane, et
al., 2005; see also Deacon et al., 2008). However, unlike panic disorder or PTSD, GAD
does not have a strong association with physical disorders except for gastrointestinal ill-
nesses (Rogers et al., 1994; Sareen, Cox, Clara, & Asmundson, 2005). GAD, then, may
be almost as common in primary care settings as major depression (Olfson et al., 2000),
a finding that is consistent with our previous discussion of GAD as a distress disorder.

Gender and Ethnicity

There is a strong gender difference in GAD, with the disorder twice as common in
women. DSM-III-R GAD had a 12-month prevalence of 4.3% for women and 2% for
men, and lifetime prevalence of 6.6% for women and 3.6% for men (Kessler et al.,
1994). In some countries women had lower rates of GAD, although the most consistent
pattern is a female gender bias in prevalence rates (e.g., Gater et al., 1998). Others have
found that women with GAD may have a higher lifetime rate for an additional anxi-
ety disorder (Yonkers, Warshaw, Massion, & Keller, 1996) and that comorbid GAD is
associated with greater probability of seeking professional help (Wittchen, Zhao, Kes-
sler, & Eaton, 1994). Significant gender differences have not been found in severity of
clinical presentation, level of impairment, presence of comorbid depression, or response
to pharmacotherapy for GAD (Steiner et al., 2005).