Gabapentin Treatment of Mood Disorders

OBJECTIVE: To determine if gabapentin is effective either as adjunctive treatment or as monotherapy for major affective disorders in a naturalistic setting. METHOD: All charts of patients meeting DSM-IV criteria for bipolar disorder or unipolar major depressive disorder treated with gabapentin in a private psychiatric practice were reviewed and clinical response was assessed retrospectively using the Clinical Global Impressions scale for Improvement (CGI-I). RESULTS: Gabapentin was moderately to markedly effective in 30% (15/50) of patients, with statistically nonsignificant differences between patients with bipolar disorder type I, bipolar disorder type II and NOS, and unipolar major depressive disorder. 70% reported side effects, mainly sedation, with 16% of the total sample discontinuing treatment due to adverse events. CONCLUSION: Gabapentin appears to be somewhat effective as add-on treatment in a subgroup of patients with mood disorders in a naturalistic setting. Prospective, controlled studies are required to clarify these pilot data.