Propranolol and depression: a reevaluation based on a pilot clinical trial.

A wide range of neuropsychiatric side effects are attributed to propranolol including visual hallucinations, somnulence, memory impairment, decrease in response time, dizziness, confusional states, insomnia, nightmares, fatigue, sedation and depression. Benson et al., in a summary review of several clinical studies of 5,846 patients being treated with a variety of beta adrenergic blocking agents, listed depression as a rare side effect of propranolol that was usually reported only after long term treatment at high doses. Despite the widely circulated attribution that depression is a side effect of propranolol, there is a paucity of evidence to directly link this drug with clinically significant mood disturbance. For example, the most widely quoted reference attributing propranolol as a depressogenic agent was a "letter to the editor" which was a retrospective, uncontrolled, unblinded study that did not use a standardized depression rating scale. Most of the evidence linking propranolol to depressive symptoms have derived from scattered case reports in which the onset of depressive symptoms were attributed to this agent. Given the well known cyclic onset and remissions of affective disorders, and the prevalence of depression in the general medical population as a whole, the role of propranolol in these cases is debatable.