Twenty-four healthy male volunteers were given 60 mg of propranolol hydrochloride (a β-adrenergic blocking agent) or placebo in divided doses given orally during the 12 hours preceding experimental procedures. As a group those subjects receiving propranolol had significantly lower initial anxiety levels measured from speech samples. A stress interview was followed by increases in anxiety scores to comparable levels in both groups.
Plasma free fatty acid (FFA) determinations did not differ significantly for the two groups, either initially or during the experimental period. However, pulse rate at the end of the 55-minute session was significantly lower for subjects on propranolol. The correlation between anxiety scored from the initial speech sample and FFA level was positive and significant for the placebo subjects and negative for the propranolol group. Propranolol administered orally may have value as an antianxiety agent and in addition is seen as providing an avenue for the exploration of psychobiological relationships.