Evaluating antianxiety agents in humans: experimental paradigms.

Conventional clinical trials using parallel groups are relatively insensitive to the effects of psychotropic drugs, especially antianxiety agents. Experimental paradigms based on the single organism research strategy offer an alternative. A free operant avoidance procedure clearly distinguished representative psychotropic compounds, including diazepam and pentobarbital, in normal subjects, and a multiple crossover procedure clearly detected antianxiety effects of diazepam in 11 psychoneurotic patients and antipsychotic effects of chlordiazepoxide in individual schizophrenic patients. Such procedures may serve to evaluate the effectiveness of therapeutic interventions in clinical practice as well as in research.