Zuclopenthixol decanoate and haloperidol decanoate in chronic schizophrenia: a double-blind multicentre study.

Zuclopenthixol decanoate (ZPT-D) and haloperidol decanoate (HAL-D) were compared in the maintenance treatment of chronic schizophrenic patients. All patients were treated with either ZPT-D or HAL-D for at least 3 months and were then randomly allocated to treatment with either ZPT-D (100-600 mg every 4 weeks) or HAL-D (38-200 mg every 4 weeks) for 9 months. Sixty-four patients entered the study. Three patients were only assessed at baseline. Four patients in the HAL-D group were withdrawn because of deterioration. One patient in the ZPT-D group committed suicide. Fifty-six patients completed the trial. The assessment programme comprised Clinical Global Impressions by psychiatrists and nurses, the Brief Psychiatric Rating Scale (BPRS), Montgomery-Asberg Depression Rating Scale (MADRS), UKU Side Effect Scale and Simpson-Angus Scale, Ratings were made at baseline and after 12, 24 and 36 weeks of treatment. The severity of illness scores remained almost constant. The only between-group difference was recorded at month 6 in favour of ZPT-D. The BPRS total scores were reduced significantly in both groups with no between-group differences. The depression scores on the MADRS were very low. Both treatments caused few and mild side effects according to the UKU Side Effect Scale and the Simpson-Angus scale, and there were no significant differences between the groups. Both ZPT-D and HAL-D seem to be effective in the maintenance treatment of chronic schizophrenic patients and cause few side effects. The injections of ZPT-D and HAL-D can be given at 4-week intervals.