Topiramate augmentation in patients with resistant major depressive disorder: A double-blind placebo-controlled clinical trial
BACKGROUND
Despite evolution of new antidepressant treatment, clinicians still encounter challenges in the treatment of depressed patients. Looking for new medications that can potentiate the effects of current antidepressants seems to be necessary. Our objective is to survey the efficacy of topiramate augmentation in resistant major depressive disorder (MDD).


METHOD
This augmentation trial was designed as an 8-week randomized, placebo-controlled, double-blind study. Fifty three patients with DSM-IV diagnosis of MDD who had failed to respond to at least 8 weeks of treatment with an adequate dose of one of the SSRIs (fluoxetine, citalopram or serteraline) were included in the study. Patients were randomized to receive a flexible dose of topiramate (100-200 mg/day) or placebo beside their current antidepressant medication for a period of eight weeks. Outcome measures were Hamilton Depression Scale (HAM-D) and Clinical Global Impression (CGI).


RESULTS
42 patients completed the study and there were 6 and 5 dropouts in topiramate and placebo groups, respectively. The topiramate group demonstrated significant improvement over the study period based on mean HAM-D score at week 8 compared to baseline (P = .000, Z = 3.699). Those receiving topiramate demonstrated to have a mean decrease of 32.0% in HAM-D score, compared to only 5.5% for those receiving placebo. Depressed mood, suicidality, insomnia (early, middle and late), agitation and anxiety symptoms were significantly improved in the topiramate group.


CONCLUSION
Our double-blind placebo-controlled study demonstrated that topiramate augmentation potentiate the efficacy of selective serotonin reuptake inhibitors (SSRIs) in treatment of resistant major depressive disorder. Of note is that our study is preliminary and larger double-blind studies are needed to confirm the results.