Medline ® Abstracts for References 1,2

BACKGROUND: Nationally representative general population data are presented on the current, 12-month, and lifetime prevalence of DSM-III-R generalized anxiety disorder (GAD) as well as on risk factors, comorbidity, and related impairments.

METHODS: The data are from the National Comorbidity Survey, a large general population survey of persons aged 15 to 54 years in the noninstitutionalized civilian population of the United States. DSM-III-R GAD was assessed by lay interviewers using a revised version of the Composite International Diagnostic Interview.

RESULTS: Generalized anxiety disorder was found to be a relatively rare current disorder with a current prevalence of 1.6% but was found to be a more frequent lifetime disorder affecting 5.1% of the US population aged 15 to 45 years. Generalized anxiety disorder was twice as common among women as among men. Multivariate logistic regression analysis showed that being older than 24 years, separated, widowed, divorced, unemployed, and a homemaker are significant correlates of GAD. Consistent with studies in treatment samples, we found that GAD was frequently associated with a wide spectrum of other mental disorders, with a lifetime comorbidity among 90.4% of the people who had a history of GAD.

CONCLUSION: Contrary to the traditional view that GAD is a mild disorder, we found that the majority of people with GAD, whether they were comorbid or not, reported substantial interference with their life, a high degree of professional help seeking, and a high use of medication because of their GAD symptoms. Although lifetime GAD is highly comorbid, the proportion of current GAD that is not accompanied by any other current diagnosis is high enough to indicate that GAD should be considered an independent disorder rather than exclusively a residual or prodrome of other disorders.

CONTEXT: Little is known about lifetime prevalence or age of onset of DSM-IV disorders.

OBJECTIVE: To estimate lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the recently completed National Comorbidity Survey Replication.

DESIGN AND SETTING: Nationally representative face-to-face household survey conducted between February 2001 and April 2003 using the fully structured World Health Organization World Mental Health Survey version of the Composite International Diagnostic Interview.

PARTICIPANTS: Nine thousand two hundred eighty-two English-speaking respondents aged 18 years and older.

MAIN OUTCOME MEASURES: Lifetime DSM-IV anxiety, mood, impulse-control, and substance use disorders.

RESULTS: Lifetime prevalence estimates are as follows: anxiety disorders, 28.8%; mood disorders, 20.8%; impulse-control disorders, 24.8%; substance use disorders, 14.6%; any disorder, 46.4%. Median age of onset is much earlier for anxiety (11 years) and impulse-control (11 years) disorders than for substance use (20 years) and mood (30 years) disorders. Half of all lifetime cases start by age 14 years and three fourths by age 24 years. Later onsets are mostly of comorbid conditions, with estimated lifetime risk of any disorder at age 75 years (50.8%) only slightly higher than observed lifetime prevalence (46.4%). Lifetime prevalence estimates are higher in recent cohorts than in earlier cohorts and have fairly stable intercohort differences across the life course that vary in substantively plausible ways among sociodemographic subgroups.

CONCLUSIONS: About half of Americans will meet the criteria for a DSM-IV disorder sometime in their life, with first onset usually in childhood or adolescence. Interventions aimed at prevention or early treatment need to focus on youth.