Antiaggressive effect of lithium ion in man.

In studies of the psychopharmacology of human aggression, 'aggression' should be related to easily identifiable behavior: angry threats or actual assaults. Aspects of behavior not meeting these criteria but relevant to a study of aggression should be described using appropriate terms such as social dominance, initiative, etc. With these conventions, examination of the heterogeneous literature on lithium treatment of aggression demonstrates that lithium ion exerts an antiaggressive effect in man. A number of hypotheses for the antiaggressive effect are examined using previous studies and new behavioral and biochemical data. It is concluded that the anti-aggressive effect is not due to any of the following: lithium toxicity or side effects; subjective or objective weakness; increased reaction time; reduced coordination or motor performance; frank cognitive deficits; hypothyroidism; reduction of serum testosterone; placebo effect; or underlying manic-depressive illness. Putative "thymoleptic" properties of lithium are too ambiguous to constitute an explanation of lithium's actions in man.