Dr Wehr's more parsimonious explanation is a valuable addition to my case report. However, previous attempts to wean the patient from tricyclic maintenance had resulted in unbearably painful depression. During a subsequent hospitalization for pneumonia, the patient's internist and I withdrew carbamazepine to evaluate any possible blood toxicity. Within a day, the patient complained of dysphoria and was becoming steadily more depressed. Carbamazepine therapy was resumed within the week, and the patient's mood improved.