The authors performed a 6-week, randomized, double-blind, placebo-controlled, parallel-group trial of carbamazepine (400 mg/day) with 21 agitated subjects (16 completers) who had been treated unsuccessfully with antipsychotics. There was greater improvement for the carbamazepine group on the Clinical Global Impression of Change (P=0.055) and the Brief Psychiatric Rating Scale (BPRS) Hostility item (P=0.009), with a trend toward worsening on the BPRS Hallucination item (P=0.067). Overall, carbamazepine showed modest clinical benefit in these subjects, who had not responded to antipsychotics, and particular benefit for hostility. The effect on global ratings was similar to those found in an earlier report in nursing home residents.