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

Previous studies in predominantly bipolar patients have suggested that gabapentin may be useful in treating mood disorders. This report describes its efficacy and tolerability as an adjunctive agent in treatment-resistant depression.

A chart review was conducted on 27 outpatients presenting with a depressive disorder in whom gabapentin was added to ongoing treatment with a conventional antidepressant to which patients had not responded after at least 6 weeks. The majority of patients had either prominent anxiety or a history of soft bipolar features, but patients with bipolar I disorder were excluded. Clinical state and adverse effects were assessed retrospectively at each visit.

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 significantly from baseline to endpoint. Overall, 37.0% (n=10) of patients were responders at endpoint; another 18.5% (n=5) manifested a transient response not sustained to endpoint. Gabapentin was well tolerated; the most common adverse effects were fatigue, sedation, dizziness, and gastrointestinal symptoms.

Treatment was uncontrolled and efficacy assessments were retrospective.

These findings suggest that gabapentin may be of adjunctive benefit in the management of treatment-resistant depression.