The effects of several anorexigenics on monkey social behavior

The effects of fenfluramine HCl, diethylpropion HCl, and methylphenidate HCl on social behavior were studied in a heterosexual group of stumptailed monkeys (M. arctoides). Subjects were treated concurrently (i.e., every monkey received the same treatment on a given day). The range of doses studied was: fenfluramine (1.0-10 mg/kg), methylphenidate (1.0-5.0 mg/kg), and diethylpropion (2.0-20 mg/kg). In general most drug/dose combinations produced decreases in social interactions. However, there was one notable exception; presenting was dramatically increased following dosing with methylphenidate and diethylpropion. Some of the solitary behaviors recorded were also observed to increase, notably, vocalization and self-grooming, which at the higher doses of diethylpropion and methylphenidate took the form of intensely idiosyncratic stereotypies. Finally, food consumption was observed to decrease in some subjects (more dominant) and increase in others (less dominant) indicating that social variables may interact with pharmacological variables.