Carbamazepine as adjunct or alternative to lithium in the prophylaxis of recurrent affective disorders.

Patients with affective disorder insufficiently responding to prophylactic lithium present a major problem to maintenance pharmacotherapy. The present retrospective study tested the efficacy of carbamazepine in 73 such patients. The patients who were switched from lithium to carbamazepine monotherapy had additional benefit, but not those switched to combined lithium plus carbamazepine. This failure to replicate a number of recent pilot studies showing synergistic effects of lithium and carbamazepine may however have been due to a heterogeneity concerning the combined effects of some negative response predictors, although none of these was significant in itself. Nevertheless, synergism cannot be taken as guaranteed. Prospective controlled trials are needed.