Effects of housing conditions and social behavior on methamphetamine self-administration in male and female rats.

Abstract

Social support is a potentially protective factor against substance use disorders (SUDs). Previous studies in animal models for SUDs have shown that when females are pair housed, they have lower motivation for cocaine and methamphetamine (METH) than females who are single housed. In males, however, social housing has not had the same beneficial effect. This study investigates effects of social housing on METH self-administration in females or males when both cage mates are self-administering METH. The study also investigated how the quality of the relationships changed after METH self-administration. The results show that singly housed females self-administered more METH than socially housed females, while males in both social housing conditions self-administered METH at the same rate. The social behavior data showed that females given saline spent more time apart, however the females given METH spent more time together, suggesting that their social behavior may play a role in the attenuation of METH self-administration. Males' social behavior remained unchanged after METH and the dominant male in a pair self-administered more METH than the non-dominant male. Females' self-administration was not affected by dominance. The results of this study show that social housing provides some protective benefits to females, but not males, for METH self-administration. Further, the type of relationship between cage mates affects males' self-administration and may explain why social housing with a same sex mate is not beneficial for males.