Two multicenter, double-blind trials were conducted in adults with DSM-III (American Psychiatric Association 1980) defined Obsessive Compulsive Disorder (OCD), comparing clomipramine (Anafranil, CMI) up to 300 mg daily with placebo. Of 519 patients evaluated, 260 received CMI for up to 10 weeks. More than half of the CMI treated patients were significantly improved, approximately 30 percent were minimally improved, and 15 percent showed no improvement after CMI treatment. The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used to assess treatment effects and attempts were made to correlate change in Y-BOCS score from baseline with a number of baseline characteristics, including age, sex, duration of OCD, baseline Y-BOCS score, baseline Hamilton Rating Scale for Depression (HAM-D) score, presence or absence of secondary depression, and predominance of obsessions or compulsions. Pearson and/or Spearman correlations failed to reveal any statistically significant correlations between outcome and any of the baseline characteristics studied. While the differences were not statistically significant, it did appear that male patients and patients with a longer duration of illness may be less likely to respond to CMI treatment; however, the overall conclusion from this analysis is that none of the variables studied is a reliable predictor of responses to treatment with CMI.