Changes Depression- and Anxiety- like Behaviors following Selective Breeding for Cocaine Reinforcement.

The LS and HS are rat lines selectively bred for altered cocaine self-administration. Given the importance of mental health in substance use, these lines were evaluated for putative depression- and anxiety- like behaviors through forced swimming and exploration of a plus maze. We found increases of struggling in LS males, climbing in LS females, and swimming in HS males; with biphasic effects on immobility in the HS strain. HS rats had fewer entries into and less time spent in open arms of the plus maze, consistent with greater anxiety-like behavior, which may contribute to enhanced drug taking.