Background: The clinical Global Impression Scale (CGI) is commonly used as a primary outcome measure in studies evaluating the efficacy of treatments for anxiety disorders. The current study evaluated the psychometric properties and predictors of clinicians' ratings on an adapted version of the CGI among individuals with social anxiety disorders.
Method: An independent assessor administered the CGI Severity of Illness and Improvement ratings to 123 patients at baseline and the subset of treated patients again mid- and post-treatment.
Results: Improvement ratings were strongly related to both concurrent Severity of Illness and changes in Severity of Illness ratings from baseline. Additionally, both CGI ratings were positively correlated with both self-report and clinician-administered measures of social anxiety, depression, impairment and quality of life. Measures of social anxiety symptoms accounted for a large portion of the variance in Severity of Illness ratings, with significant additional variance accounted for by measures of impairment and depression. Changes in social anxiety symptoms from baseline accounted for significant variance in Improvement ratings, but no significant additional variance was accounted for by changes in impairment and depressive symptoms.
Conclusions: Our findings support the utility of the CGI as an index of global severity and symptom-specific improvement among individuals with social anxiety disorder.