PREGABALIN AUGMENTATION IN TREATMENT-RESISTANT OBSESSIVE-COMPULSIVE DISORDER : CASE SERIES

Abstract

Background Obsessive compulsive disorder (OCD) is a syndrome characterised by obsessions and compulsions, as well as other neuropsychiatric features, and is often associated with primary psychiatric disorders and various neurologic conditions. Despite the beneficial effect of selective serotonin reuptake inhibitors (SSRIs) in OCD, up to 40% of patients remain refractory to treatment. The therapeutic limitations of standard psychopharmacological treatments of OCD warrant the investigation of other treatment strategies. One potential candidate is pregabalin, a novel analogue of the inhibitory neurotransmitter gamma amino butyric acid (GABA). Pregabalin has been shown to be efficacious in other anxiety disorders and in a recent open-label trial was found to lead to a significant improvement in clinical symptoms in treatment-resistant OCD patients . We present findings from a case series of inpatients with severe, complex, and resistant obsessive-compulsive disorder (OCD) whose treatment was augmented with pregabalin. Methods: The National Obsessive Compulsive Disorder/Body Dysmorphic Disorder (OCD/BDD) Service at South West London and St George’s Mental Health NHS Trust, affiliated with St George's University of London, is one of five nationally funded tertiary centres providing outreach across all regions in England. This case series consisted of 16 patients, 11 men and 5 women, with severe OCD, as defined by a score of 30 or more on the Yale-Crown Obsessive Compulsive Scale (YBOCS), who were treated with pregabalin during the course of their admission to the above unit in the time period December 2013-June 2015. We compared YBOCS scores at discharge against the patient’s initial severity and also examined patient notes to gather anonymised qualitative data for case vignettes to further elucidate their treatment experiences. Results The median age of patients was 38.5 years at the time of admission and the median duration of admission was 6 months. The median dosage of pregabalin at the time of discharge was 300mg/day, representing a median dose increase of 150mg/day from admission. Improvement in patients’ OCD symptoms was observed with a median reduction in YBOCS score of 13, reflecting a median 33% reduction in symptom severity. Case vignettes showed that adjunctive pregabalin was generally well-tolerated. Discussion In severe OCD a 30% reduction in symptom severity is seen as a reasonable aim; the improvement seen therefore represents a clinically meaningful change. To the best of our knowledge, so far only one study has been published looking at pregabalin as an adjunctive treatment in treatment-resistant OCD. Our findings were consistent with theirs, and in addition we were able to examine changes in YBOCS scores over a longer duration. There are several important limitations to this case series - namely, its small sample-size, lack of control group, the fact that participants were non-blinded, and that we were not able to control for the therapeutic effects of the hospital environment. However, given the lack of currently available data around the use of pregabalin as an adjunctive agent, this data represents a meaningful step in this burgeoning area of research. We would encourage further research that addresses the aforementioned limitations.