Behavioral changes in a juvenile primate social colony with chronic administration of d-amphetamine.

Three selected members of a stable juvenile primate social colony of six, peer-raised, one-year old Stumptail macaques received 0.5 mq/kg of d-amphetamine sulfate daily for four weeks. Amphetamine significantly reduced play activity to a minimum in the treated monkeys throughout the treatment period. These animals preferred huddling with eyes open, although no sedation was apparent. As the treatment period progressed, stereotyped behavior developed, rising significantly during the final week of treatment. This model may be useful in studying the seemingly "paradoxical" quietening effect of amphetamine in children.