Treatment of Generalized Anxiety Disorder

Generalized anxiety disorder (GAD) is a common condition, with a lifetime prevalence of approximately 5% in the United States adult population according to the Epidemiological Catchment Area (ECA) study [1]. In comparison, Kendler et al [2] reported a lifetime prevalence of 3.6%. The National Comorbidity Survey reported a lifetime prevalence of 5.1% [3]. An international (World Health Organization) study indicated that GAD was the second most frequent psychiatric disorder after depression in the primary care setting, with approximately 8% of primary care patients meeting diagnostic criteria [4,5]. Risk for GAD is slightly higher among women. GAD has a relatively early onset and is typically a chronic illness [6]. The ECA survey reported that approximately one third of individuals with GAD had an age of onset in the teens or early twenties [1]. Frequently, however, the first contact with a health professional is not until young adulthood or later. The course of illness of GAD tends to be chronic and recurrent. The ECA survey found that almost 50% of individuals who had ever experienced GAD continued to be ill at the time of interview, and the mean duration of illness was reported to be 6 to 10 years [1]. Significant distress and disability are associated with GAD. Excellent information is currently available on the disability and quality of life effects of GAD from the ECA community survey [1] and from a multisite survey of psychiatric outpatients [7]. The overall picture for GAD is one of significant psychosocial impairment. Of those patients who were working, 38% had missed at least 1 week of work in the past year due to their anxiety [7]. Greenberg et al [8] estimated the cost of all anxiety disorders to be approximately $42.3 billion in 1990 in the United States. Rice and Miller [9] reported similar economic costs.