Different studies published in the last years have focused on the psychotropic effects of carbamazepine (CBZ). This study tries to investigate the efficacity of CBZ as an adjunct treatment of schizophrenia. 20 patients with a diagnosis of paranoid schizophrenia, according to the RDC, have been investigated by double-blind method. Subjects are divided in two groups (n = 10). The first one is treated with CBZ (with dose in order to reach a plasma level between 8-12 mg /l) and Haloperidol (oral fixed dose: 30 mg /day). The second group only with Haloperidol (same dose). Clinic and psychopathological disturbances are evaluated with the BPRS, and secondary effects with the UKU scale. A clinical improvement (90%, measured by the BPRS) was observed for both groups, without significant differences. Patients treated with CBZ show an important reduction of neurological secondary effects related to neuroleptics (Haloperidol). Carbamazepine appears to be a useful treatment, combined with neuroleptics, for acute schizophrenic episodes.