Adjunctive gabapentin in treatment-resistant depression: a retrospective chart review

Background: Previous studies in predominantly bipolar patients have suggest ed that gabapentin may be useful in treating mood disorders. This report de scribes its efficacy and tolerability as an adjunctive agent in treatment-r esistant depression. Methods: A chart review was conducted on 27 outpatient s presenting with a depressive disorder in whom gabapentin was added to ong oing treatment with a conventional antidepressant to which patients had not responded after at least 6 weeks. The majority of patients had either prom inent anxiety or a history of soft bipolar features, but patients with bipo lar I disorder were excluded. Clinical state and adverse effects were asses sed retrospectively at each visit. Results: Mean gabapentin trial duration was 15.2 +/-7.8 weeks, with a mean final dose of 904 +/- 445 mg/day (range, 300-1800 mg/day). Clinician-rated measures of clinical state improved sign ificantly from baseline to endpoint. Overall, 37.0% (n = 10) of patients we re responders at endpoint; another 18.5% (il = 5) manifested a transient re sponse not sustained to endpoint. Gabapentin was well tolerated; the most c ommon adverse effects were fatigue, sedation, dizziness, and gastrointestin al symptoms. Limitations: Treatment was uncontrolled and efficacy assessmen ts were retrospective. Conclusion: These findings suggest that gabapentin m ay be of adjunctive benefit in the management of treatment-resistant depres sion. (C) 2001 Elsevier Science B.V. All rights reserved.