Can aggressive behavior in humans be modified by beta blockers?

Persistent aggressive behavior may develop in patients with brain disorders of various types, including seizure disorders, mental retardation, metabolic disorders, head injury, and in some instances schizophrenia. Although a neurochemical basis for aggression in these cases is unclear, a hyperadrenergic state is considered to be one possibility. This has led to the hypothesis that beta blockers may be useful in the control of aggression. The original assumption was that the site of antiaggressive action of beta blockers is in the brain. However, the antiaggressive efficacy of nadolol, which does not cross the blood-brain barrier to any great extent, suggests a peripheral site or sites. A review of several studies in which both old and young aggressive patients with various organic brain disorders received propranolol showed that aggressive behavior was reduced in 75 (86%) of 87. These results are encouraging because none of the patients had responded to earlier drug treatment. However, with the exception of one study of nine patients, none of the studies were controlled for placebo effects and most were retrospective. Preliminary results suggest tentative guidelines for treatment of aggressive behavior with beta blockers. Further studies are needed, and these should use a prospective, longitudinal double-blind design; large enough patient samples to permit testing hypotheses about disease-specific or symptom-specific responses to beta blockers; and improved instruments for measuring and classifying aggression.