Methodological issues in psychopharmacological research: chlorpromazine--a case in point.

Past research on the relative efficacy of powerful psychotropic agents has generally relied on group designs, which may mask critical individual differences in drug response. This and other methodological inadequacies raise questions about much of the vast literature in support of the clinical efficacy of chlorpromazine and similar drugs. A research strategy employing within-subJect designs, using a single subject as his own control, is suggested as advantageous in assessing individual drug effects at specific dosage levels.