This book examines the impact of different doses of cocaine on three interrelated measures related to affective behaviours between adolescent and adult mice in order to assess the range of affective and rewarding responses, measure of despair, activity, and reward were used. Such methods included the forced swim test (FST), motor activity (MA), and the conditioned place preference (CPP) tests, respectively. Cocaine was selected, in part, because of its robust psychostimulant properties, its use by millions of substance abusers world-wide, and its well understood mechanism of action. This study may help explain some of the neurobiological underpinnings of these finding because cocaine was especially effective in reducing despair-related behaviour in adolescence compared with adults, yet less effective in as an euphoric agent.