Differential sensitivity to the effects of psychotropic drugs: psychotics vs normals; Asian vs Western populations.

The effects and side-effects of psychotropic drugs are determined by many variables, and the host factor is one of the most important. A lower sensitivity of schizophrenics than normals to the sedative effect of chlorpromazine and a manic depressives to imipramine were demonstrated quantitatively by a higher percent time of waking EEG following medication. The mean therapeutic dose of chlorpromazine for the manic state was found to be much lower in Japanese than in Western populations in a controlled study comparing the antimanic efficacy of carbamazepine and chlorpromazine. A lower therapeutic dose in Asian populations has been reported also on other antipsychotic drugs, lithium, and tricyclic antidepressants. The lower therapeutic dose level was discussed from the standpoint of transcultural psychopharmacology.