Social isolation of rhesus monkeys for the first 6 to 12 months of life produces severe and persistent behavioral effects including social withdrawal, rocking, huddling, self-clasping, stereotyped behaviors, and inappropriate heterosexual and maternal behaviors as adults. The mechanisms by which these effects are produced are uncertain and require additional investigations.
The social isolation syndrome has been likened to several human psychopathological states, but exact labeling of it in human terms is premature at present. Rather the syndrome should be viewed in terms of its heuristic value as a model system for further clarifying the interactions among early rearing conditions, their possible neurobiological consequences, and subsequent social behaviors.
McKinney WT. Primate Social IsolationPsychiatric Implications. Arch Gen Psychiatry. 1974;31(3):422-426. doi:10.1001/archpsyc.1974.01760150122018