Trials were coded for the following characteristics: (1) participant mean age; (2) percentage of comorbid TS/CTD, ADHD, depressive disorders (major depressive disorder, dysthymia), and anxiety disorders (social phobia, generalized anxiety disorder, separation anxiety disorder, panic disorder); (3) baseline OCD severity; (4) number of 1-hour therapy sessions (for CBT trials); (5) percentage of SRI medication at baseline (for CBT trials); (6) active treatment attrition; (7) measure of treatment efficacy, response, and remission; (8) effect size (Hedges’ g), treatment response, and symptom/diagnostic remission; (9) treatment subtype (ERP or CT for CBT trials; CMI or SSRI for SRI trials); (10) comparison condition; and (11) study methodological quality. Comorbid disorders were selected due to their potential impact on treatment outcome.[42–45] Comparison conditions were classified into two categories: non-active interventions (e.g., waitlist, placebo, treatment-as-usual); and active interventions (e.g., desipramine, relaxation training). Study methodology was assessed using a 23-item scale that has been used in other meta-analyses.[63–65] Possible scores range from 0 to 46, with higher values corresponding with greater methodological rigor. Study investigators were contacted to request the above information if it was not available in published form. Trials were coded by two raters to ascertain reliability. Rater disagreement was resolved through discussion and consensus.
