Cis(Z)-clopenthixol and clopenthixol in the treatment of acute psychoses and exacerbations of chronic psychoses. A double-blind clinical investigation.

The clinical effect of cis(Z)-clopenthixol has been compared with that of clopenthixol, which is a mixture of the pharmacologically active cis(Z)-isomer and the inactive trans(E)-isomer. In the 4-week double-blind trial were included 20 patients with acute psychoses and exacerbations of chronic psychoses, mainly schizophrenics. Ratings evaluating severity of illness, therapeutic effect, possible interference of side effects with the patient's functioning were done at weeks 0, 2, and 4, at which occasions also the BPRS was filled in. All patients improved, most of them so much that their final BPRS-score was less than half their initial score. In conclusion, the antipsychotic effect of cis(Z)-clopenthixol was found equal to that of clopenthixol whereas the cis(Z)-isomer on a mg/mg basis was twice as active as clopenthixol. Side effects were few, similar, and equally frequent in the two groups, extrapyramidal side effects and drowsiness being the most common.