N Fairbanks1, C Forbes1,2, S Stringfield1,2, A Sved1,2, J Zeak1, M Seney1,2, Y Huang1,2, M Torregrossa1,2, C McClung1,2

Adolescence is a period of substantial neurodevelopment and behavioral changes, increasing their vulnerability to drug use and developing substance use disorders. Developmental changes in sleep and circadian rhythms, primarily represented by a shift towards a more evening chronotype, are increasingly recognized as relevant to understanding adolescent addiction vulnerability. Thus, this natural variation in sleep and circadian traits seen in adolescence may be associated with indicators of risk for substance use, such as altered cognitive function, and impulsivity. To investigate this interaction, male and female adolescent heterogenous stock rats were screened on measures of sleep duration and circadian chronotype prior to being either tested on measures of impulsivity, attention and cognition using the 5-choice serial reaction time task (5-CSRTT), and for propensity to self-administer nicotine, or underwent electrophysiology recordings of Nucleus Accumbens (NAc) action potential firing. Our results showed that circadian period had the strongest relationship with impulsivity. Specifically, rats with a short circadian period were more impulsive and made more premature responses. We also found that circadian period was strongly associated with measures of nicotine self-administration, where a longer circadian period was associated with more total nicotine intake and greater lever pressing. These results suggest that natural variation in sleep and circadian traits, like having a short or long circadian period, may be associated with different risk factors of substance use disorders.

1Department of Psychiatry, 2Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA

Funding Support: National Institute on Drug Abuse (USA), P50DA046346