The fact that adolescents commonly initiate drug use in social settings is well established. Both clinical and preclinical research has investigated how social interaction is altered by a variety of drugs of abuse. What is less understood is how the rewarding value of drugs of abuse is affected by the presence of social peers. This dissertation aimed to investigate the interaction of morphine and social play on conditioned place preference (CPP) in adolescent male Sprague Dawley rats, using both behavioral and immunohistochemistry (IHC) methods. Rats were exposed to morphine (0, 1, or 3 mg/kg; s.c.), social interaction, or a combination of both and tested in a modified CPP procedure. Behavioral results indicate that, while doses of morphine used produced only weak CPP across experiments, they were sufficient to reduce the rewarding effect of social interaction. IHC results suggest that this finding may be due to reduced activation in NAc shell. Taken together, the results of this dissertation may help to provide an explanation as to why persons with opioid use disorder spend less time interacting with social peers, compared to non-dependent persons
