Effects of Adolescent Social Stress on Binge Drinking in Mice

Social stress during adolescence has been linked to increased ethanol intake in adulthood. It is unknown if social stress during adolescence also causes changes in the patterns of drinking, such as drinking in bouts instead of spreading out each drink. Animal models of social stress utilize mice and social isolation. Half of the mice used in this experiment were isolated for their adolescent period, whereas the other half were housed in groups. In Phase 1, mice completed a two-bottle choice Drinking in the Dark (DID) procedure in order to model binge drinking and measure ethanol intake. In Phase 2, mice completed a free choice behavioral task, choosing between milk alone and milk mixed with ethanol. Phase 1 showed increased ethanol intake in females and in mice that were isolated. Within this phase, there was also a sex x treatment interaction, with isolated males drinking significantly more alcohol than social males. Phase 2 also showed that females drink more ethanol than males but showed no difference in their pattern of drinking. In addition, there was a sex x treatment x reinforcer interaction, demonstrating that isolated females drank significantly more vehicle than any other group. These results reaffirm that adolescent social stress is linked to increased ethanol intake, yet may not change the pattern of drinking. This suggests that the effects of social isolation during adolescence on patterns of drinking should be investigated further.