Venlafaxine in Treatment Resistant Obsessive-Compulsive Disorder

To the Editor: Selective serotonin reuptake inhibitors (SSRIs) are the first line treatment option for obsessive compulsive disorder (OCD). However, nearly 40% to 60% of patients do not respond satisfactorily to SSRIs.¹ There is evidence to suggest that venlafaxine, a serotonin norepinephrine reuptake inhibitor, is useful in the treatment of OCD. However, only one study has examined its effectiveness in patients who have not responded to multiple SSRI trials.² Hence, we report a series of five patients who responded to venlafaxine and maintained sustained improvement over an extended period following failure to respond to multiple SSRI trials.

The patients were being treated at the OCD clinic of the National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India. They met DSM-IV criteria for OCD and were evaluated with the Yale-Brown obsessive compulsive scale (YBOCS),³ the Mini International Neuropsychiatric Interview plus⁴ and the Clinical Global Impression scale (CGI).⁵ Clinical characteristics and treatment details are given in Table 1. Treatment resistance was defined as nonresponse (<25% YBOCS improvement and CGI-Improvement score ≥3) to adequate trial (12 weeks) of at least two SSRIs.¹

It is evident from the table that all the patients had failed to show response to multiple trials of SSRIs and augmentation strategies. Three of them had not shown response to even addition of cognitive-behavior therapy (CBT). At the end of treatment, all the five patients showed significant improvement with symptom reduction of ≥35% over the pretreatment YBOCS scores, which is considered as a significant treatment response in the treatment trials of OCD with a CGI-I score of 1 or 2.¹ Moreover, they maintained improvement over long periods of follow-up without any relapses. Only one patient reported gastritis, which required treatment with proton pump inhibitor. Other four patients did not report any untoward side effects and seemed to tolerate venlafaxine well.

Our case series adds to the existing literature that venlafaxine may be beneficial in individuals with OCD who have not responded to multiple SSRIs. A previous open label study also found venlafaxine to be beneficial in up to 76% of the patients who did not respond to at least one SSRI trial.² That three of our patients who responded to venlafaxine had not responded previously to even CBT underscores the need to examine the efficacy of venlafaxine systematically in treatment resistant OCD. The findings of our report must be interpreted with caution because of the retrospective nature of the study, small sample size, and absence of a comparison group.