Stabilization of psychophysical performance of healthy volunteers by propranolol—a contribution to differential psychopharmacology

Eight volunteers out of 81 medical students of a one-year register were selected in a two-step procedure by means of a motivation Q-sort. Of these, four were motivated for success (S.M.), whereas four were motivated for failure (F.M.). Following a stratification step, two subjects each from each group were orally given propranolol (0.6 mg/kg) or placebo in a double-blind trial. Test inventory; flicker fusion frequency; determination performance in normal and tailored testing; subjective self-rating; blood pressure; pulse. Evaluation was accomplished in the conventional dose-related way (propranolol versus placebo) and in a serum level oriented approach common in differential psychopharmacology, by judging the personality structure (nervousness, neuroticism, extraversion) and the volunteers' motivation. It was found that propranolol when compared to placebo did not alter the vigilance, performance and subjective assessment of the volunteers; hence, the next step of evaluation was made regardless of the treatment. The initial performance of F.M. subjects as measured on the determination test unit was substantially poorer when compared to S.M. volunteers. During a 7.5-h period after application, the reaction time of F.M. subjects was noted to improve both as a result of training due to repeated tests and as a function of propranolol. As only a small number of volunteers was available for the investigation, further studies are encouraged to verify performance of F.M. subjects.