Acute and prophylactic effects of anticonvulsants in bipolar depression

The anticonvulsants carbamazepine and valproate are now widely recognized and used mood stabilizers as adjuncts or alternatives to lithium carbonate. Like lithium, however, they appear to have better antimanic than antidepressant properties. In contrast, initial data suggest that lamotrigine may be an exception to this rule, with better evidence of acute and prophylactic antidepressant than antimanic effects emerging in controlled trials. Gabapentin is being widely used, although its primary antimanic and antidepressant properties have not been delineated in controlled trials, but it does appear to be useful in a number of syndromes that are often comorbid with bipolar depression, including anxiety, social phobia, obsessive-compulsive disorder, alcohol withdrawal syndromes, pain syndromes, and a variety of sleep disorders. The data are mixed regarding topiramate's acute antidepressant properties, although its positive side-effects profile of inducing weight loss may make it a particularly useful adjunct independent of its ultimate mood stabilizing properties. While initial data with tiagabine are not promising, the possible antidepressant effects of two of the newest anticonvulsants levetiracetam and zonisamide are just beginning to be evaluated. Thus, several of the compounds originally FDA-approved as anticonvulsants appear promising for their acute and long-term antidepressant effects in bipolar illness, and much work remains to be done to identify clinical and biological markers of response to individual agents and assess how they may best be utilized in clinical practice. (C) 2002 Elsevier Science B.V. All rights reserved.