The clinical use of gabapentin in bipolar spectrum disorders

BACKGROUND: with increasing awareness of lithium's limitations, several new anticonvulsants had been tested for their mood stabilisation during recent years. Among the innovative third generation mood stabilizing anticonvulsants, gabapentin (GBP) seems to have a broad spectrum of efficacy, although no certain data are available as to its efficacy and use in clinical practice. Accordingly, an extensive review on this subject has been carried out. METHODS: A computer-generated search of the biomedical literature and abstract books of the more important scientific psychiatric congresses until June 2000 was undertaken to identify all pertinent case reports, case series and studies of GBP as monotherapy or adjunctive therapy in mood disorders. We identified 40 open-label studies on the use of GBP in at least 600 patients with bipolar disorder (BP), manic, depressed, or mixed episodes and unipolar depression and four controlled studies. RESULTS: The 40 open-label studies and two of the controlled trials suggested that GBP may have a role as adjunctive agent in the treatment of patients with bipolar disorders particularly when complicated by co-morbid anxiety disorder or substance abuse. GBP is usually very well tolerated and has no pharmacological interference with other mood stabilisers. However, in the other two double-blind studies GBP has not been found to be efficacious in the treatment of refractory mania or refractory bipolar depression. CONCLUSIONS: Although failing to show clear antimanic efficacy in randomized trials, gabapentin still remains a clinically useful agent when it comes to combination treatment in refractory and co-morbid patients.