Effect of adjuvant pindolol on the antiobsessional response to fluvoxamine: a double-blind, placebo-controlled study

On the basis of recent results indicating that adjuvant pindolol has the positive effect of shortening latency to antidepressant response to selective serotonin reuptake inhibitors, the primary aim of our study was to evaluate the effect of pindolol on latency to antiobsessional response to fluvoxamine. Fifteen non-depressed obsessive-compulsive inpatients (six men and nine women) were consecutively recruited and randomly assigned to an 8-week standardized double-blind treatment with fluvoxamine and pindolol (group A) or fluvoxamine and placebo (group B). Patients were assessed weekly using rating scales for obsessive-compulsive disorder [Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), National Institute of Mental Health Obsessive-Compulsive Scale], co-occurent depressive symptoms (Hamilton Depression Scale) and global function (Clinical Global Improvement), from baseline to the end of the study. In accordance with data from the literature, response to treatment was defined as a reduction in YBOCS total scores of > or = 35% and a score on the 'global improvement' item of the Clinical Global Improvement of < 3. Data were analysed using analyses of variance with repeated measures performed on YBOCS and Hamilton Depression Scale scores to evaluate the mean quantitative response within and between groups and, additionally, employing a survival analysis to compute the percentage of responders within each group. Neither quantitative nor qualitative analysis revealed any differences between the two treatment groups, and pindolol did not shorten the latency of antiobsessional response to fluvoxamine. The results of this preliminary study indicate that different biological mechanisms underly the antiobsessional and antidepressant responses to fluvoxamine.