The American Psychiatric Association first introduced the diagnosis of generalized anxiety disorder (GAD) 2 decades ago in the DSM-III.<sup>4American Psychiatric Association  Diagnostic and Statistical Manual of Mental Disorders Washington, DC: American Psychiatric Association (1980). 

Haga clic aquí para ir a la sección de Referencias</sup> Before that time, GAD was conceptualized as one of the two core components of anxiety neurosis, the other being panic.<sup>3American Psychiatric Association  Diagnostic and Statistical Manual of Mental Disorders Washington, DC: American Psychiatric Association (1968). 

Haga clic aquí para ir a la sección de Referencias</sup> A recognition that GAD and panic, although often occurring together, are sufficiently distinct to be considered independent disorders led to their separation in the DSM-III.

The DSM-III definition of GAD required uncontrollable and diffuse (i.e., not focused on a single major life problem) anxiety or worry that is excessive or unrealistic in relation to objective life circumstances and that persists for 1 month or longer. Several related psychophysiologic symptoms also were required to occur with the anxiety or worry for a diagnosis of GAD. Early clinical studies evaluating DSM-III according to this definition in clinical samples found that the disorder seldom occurred in the absence of some other comorbid anxiety or mood disorder. Comorbidity of GAD and major depression was especially strong<sup>16Breier A., Charney D.S., Heninger G.R. The diagnostic validity of anxiety disorders and their relationship to depressive illness Am J Psychiatry 1985 ;  142 : 787-797

Haga clic aquí para ir a la sección de Referencias, 17Breslau N. Depressive symptoms, major depression and generalized anxiety: A comparison of self-reports on CES-D and results from diagnostic interviews Psychiatry Res 1985 ;  15 : 219-229 [cross-ref]

Haga clic aquí para ir a la sección de Referencias</sup> and led some commentators to suggest that GAD might better be conceptualized as a prodrome, residual, or severity marker than as an independent disorder.<sup>19Breslau N., Davis G.C. Further evidence on the doubtful validity of generalized anxiety disorder [letter] Psychiatry Res 1985 ;  16 : 177-179 [cross-ref]

Haga clic aquí para ir a la sección de Referencias, 22Clayton P.J., Grove W.M., Coryell W., y al. Follow-up and family study of anxious depression Am J Psychiatry 1991 ;  148 : 1512-1517

Haga clic aquí para ir a la sección de Referencias, 46Noyes R., Woodman C., Garvey M.J., y al. Generalized anxiety disorder vs. panic disorder: Distinguishing characteristics and patterns of comorbidity J Nerv Ment Dis 1992 ;  180 : 369-379 [cross-ref]

Haga clic aquí para ir a la sección de Referencias</sup> The rate of comorbidity of GAD with other disorders decreases as the duration of GAD increases.<sup>18Breslau N., Davis G.C. DSM-III generalized anxiety disorder: An empirical investigation of more stringent criteria Psychiatry Res 1985 ;  15 : 231-238 [cross-ref]

Haga clic aquí para ir a la sección de Referencias</sup> Based on this finding, the DSM-III-R committee on GAD recommended that the duration requirement for the disorder be increased to 6 months. This change was implemented in the final version of the DSM-III-R.<sup>5American Psychiatric Association  Diagnostic and Statistical Manual of Mental Disorders, ed 3, rev Washington, DC: American Psychiatric Association (1987). 

Haga clic aquí para ir a la sección de Referencias</sup> Additional changes in the definition of excessive worry and the required number of associated psychophysiologic symptoms were made in the DSM-IV.<sup>6American Psychiatric Association  Diagnostic and Statistical Manual of Mental Disorders Washington, DC: American Psychiatric Association (1994). 

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These changes in diagnostic criteria led to delays in cumulating data on the epidemiology of GAD. Nonetheless, such data became available over the past decade. As described in more detail later, these new data challenge the view that GAD should be conceptualized as a prodrome, residual, or severity marker of other disorders. Instead, the data suggest that GAD is a common disorder that, although often comorbid with other mental disorders, does not have a rate of comorbidity that is higher than those found in most other anxiety or mood disorders. The new data also challenge the validity of the threshold decisions embodied in the DSM-IV.<sup>6American Psychiatric Association  Diagnostic and Statistical Manual of Mental Disorders Washington, DC: American Psychiatric Association (1994). 

Haga clic aquí para ir a la sección de Referencias</sup> This article begins by reviewing results from these studies on the prevalence, course, and symptom specificity of GAD. The authors then consider the important issues of comorbidity and impairment. The final section of the article discusses epidemiologic evidence on patterns of help seeking for GAD.