Should excessive worry be required for a diagnosis of generalized anxiety disorder? Results from the US National Comorbidity Survey Replication.
BACKGROUND
Excessive worry is required by DSM-IV, but not ICD-10, for a diagnosis of generalized anxiety disorder (GAD). No large-scale epidemiological study has ever examined the implications of this requirement for estimates of prevalence, severity, or correlates of GAD.


METHODS
Data were analyzed from the US National Comorbidity Survey Replication, a nationally representative, face-to-face survey of adults in the USA household population that was fielded in 2001-2003. DSM-IV GAD was assessed with Version 3.0 of the WHO Composite International Diagnostic Interview. Non-excessive worriers meeting all other DSM-IV criteria for GAD were compared with respondents who met full GAD criteria as well as with other survey respondents to consider the implications of removing the excessiveness requirement.


RESULTS
The estimated lifetime prevalence of GAD increases by approximately 40% when the excessiveness requirement is removed. Excessive GAD begins earlier in life, has a more chronic course, and is associated with greater symptom severity and psychiatric co-morbidity than non-excessive GAD. However, non-excessive cases nonetheless evidence substantial persistence and impairment of GAD, high rates of treatment-seeking, and significantly elevated co-morbidity compared with respondents without GAD. Non-excessive cases also have sociodemographic characteristics and familial aggregation of GAD comparable to excessive cases.


CONCLUSIONS
Individuals who meet all criteria for GAD other than excessiveness have a somewhat milder presentation than those with excessive worry, yet resemble excessive worriers in a number of important ways. These findings challenge the validity of the excessiveness requirement and highlight the need for further research into the optimal definition of GAD.
Ruscio
Ayelet Meron
AM
Department of Health Care Policy, Harvard Medical School, Boston, MA 02115, USA.
Lane
Michael
M
Roy-Byrne
Peter
P
Stang
Paul E
PE
Stein
Dan J
DJ
Wittchen
Hans-Ulrich
HU
Kessler
Ronald C
RC
D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology; D010342:Patient Acceptance of Health Care; D015995:Prevalence; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology