Physiological response to propranolol and diazepam in chronic anxiety

1 Twelve chronically anxious psychiatric out-patients, comprising six with somatic anxiety and six with psychic anxiety, were treated with (±)-propranolol, diazepam and placebo for one week each in flexible dosage using a balanced cross-over experimental design. 2 After each treatment, in addition to ratings completed by patient and psychiatrist, finger tremor, EEG, averaged auditory evoked response, skin conductance, heart and respiratory rate were measured. 3 Diazepam significantly increased the amount of fast activity (13.5-26 Hz) in the EEG but produced few peripheral effects apart from a reduction in finger tremor. 4 Propranolol had no central physiological effects but reduced both pulse rate and finger tremor. 5 The physiological effects of propranolol in chronic anxiety are different from those of diazepam and therapeutic benefit appears to be due to a direct effect on certain somatic symptoms.