[Serotonergic dysfunction caused by social isolation. Implications for the development of aggressiveness and...

Dysfunction of serotonergic neurotransmission has been associated with two different psychopathological syndromes--impulsive aggressivity resulting form a lack of stimulation of the "behavior inhibition system" on the one hand and the manifestation of clinical depression and compulsive syndromes on the other. The examination of primate behavior provides a model which may reconciliate these seemingly contradictory hypotheses. According to primate experiments, monoaminergic depletion results in anxious and desperate behavior only if the individual has previously been exposed to social isolation stress, which in turn induces a decrease in the central serotonin turnover rate. Young non-human primates who experience early social separation stress are anxious and fearful, while as adults they tend to be aggressive, consume excessive amounts of alcohol and are less intoxicated by alcohol intake. These observation indicate the importance of social separation stress in the pathogenesis of alcoholism and antisocial behavior and may point to prophylactic and pharmacological treatment strategies.