Background: The purpose of the present open-label study was to investigate the antidepressant efficacy of lithium and carbamazepine as augmentation strategies in unipolar depressed inpatients.
Method: Forty-six patients suffering from unipolar depression (major depressive episode according to DSM-IV criteria) were pre-treated with mirtazapine for 2 weeks initially (week -2 to week 0). Thereafter, the patients received either continuation of mirtazapine monotherapy (n = 23), combination treatment with mirtazapine and lithium (n = 13), or combination therapy with mirtazapine and carbamazepine (n = 10) for further 3 weeks (week 0 to week 3). Severity of depression was estimated weekly using the 21-item version of the Hamilton Depression Rating Scale (21-HAMD). Response was defined by a reduction of at least 50% in the 21-HAMD sum score after 3 weeks of pharmacotherapy (week 0-3).
Results: Additional administration of lithium, but not adjunctive carbamazepine significantly augmented the antidepressant efficacy of mirtazapine in the unipolar depressed patients. Moreover, carbamazepine but not lithium significantly lowered the serum concentrations of mirtazapine.
Conclusion: Whereas the clinical importance of anticonvulsants in the treatment of bipolar disorder is not in doubt, the therapeutic efficacy of antiepileptic drugs such as carbamazepine is obviously limited in the pharmacotherapy of unipolar depression.