Trifluoperazine, which is 2-trifluoromethyl-10-(3′-[1″-methylpiperazinyl-4″]-propyl)-phenothiazine dihydrochloride—a preparation manufactured by Smith, Kline and French Laboratories Limited under the description SKF5019—is the most recent phenothiazine derivative reported to have a beneficial effect on certain types of mental illness. On the basis of animal tests trifluoperazine is described as having nine times the potency of chlorpromazine in blocking the conditioned response, and its specificity is greater than that of chlorpromazine.