Reliability and validity of DSM-IV generalized anxiety disorder features.

The reliability of generalized anxiety disorder (GAD) features has been shown to be moderate, based on research utilizing the Anxiety Disorders Interview Schedule for DSM-IV (ADIS-IV), a semi-structured diagnostic interview. This may be a function of the criteria for the diagnosis of GAD, which have undergone much revision since its first inclusion in the Diagnostic and Statistical Manual of Mental Disorders. The reliability and validity of disorder feature ratings were examined in a diverse sample of patients who presented for assessment and treatment of excessive worry, generalized anxiety, or tension at an anxiety specialty clinic and who met criteria for a principal diagnosis of GAD (N=129). Internal consistency of the ratings of excessiveness of worry, uncontrollability of worry, and the associated symptom cluster was moderate to low and varied by disorder feature. Inter-rater reliability for all features of GAD and severity of the disorder varied between good and poor. Additional findings showed that the GAD features, as measured using the ADIS-IV module, have modest to strong convergent validity, varying by feature, and poor discriminant validity when tested against measures of social anxiety. Potential reasons for rater disagreement are discussed. Results are also considered in terms of how they may inform the evolving criteria for GAD in DSM-V.