Social rehabilitation of separation-induced depressive disorders in monkeys.

The authors studied a group of four monkeys reared together, repeatedly separated from each other, and then exposed to another group of four monkeys reared in surrogate-peer groups who acted as therapists. The study group was compared with the therapist monkeys, a group exposed to the same separations but not to the therapist monkeys, a control group that experienced no separations, and two additional groups of stimulus animals. The authors' findings indicate that monkeys showing depressive begaviors after repeated separations can be returned to age-appropriate social performance through repeated exposure to socially active age-mates.