Autonomic Nervous System Functioning in Heavy Drinking Adolescents: Interactions with sleep, circadian functioning, and health - Project Summary/ Abstract Heavy drinking is highly prevalent in adolescents and young adults and can lead to dangerous behavioral and health consequences. Specific mechanisms of risk for escalating drinking in adolescence and young adulthood are not well understood. The continuous communication between the heart and brain through the ANS is critical to basic regulatory processes like sleep and circadian rhythms, as well as to responses to stressors and rewards in one’s environment. In adults with alcohol use disorders, poorer ANS functioning (i.e., lower heart- rate variability [HRV] and baroreflex sensitivity [BRS]) are associated with greater reported craving and alcohol-seeking behavior; however, it is unclear how ANS functioning relates to heavy drinking below the threshold of alcohol use disorders in adolescents. The application seeks to examine autonomic nervous system (ANS) functioning, as indexed by cardiovascular probes, and its relationship to alcohol use, craving, and cue-reactivity in an adolescent/young adult sample to elucidate a potential mechanism of risk in heavy alcohol users. The central premise of the application is that ANS functioning: 1) is critical to one’s ability to self- regulate emotional response and specifically regulate responses to internal and external cues related to alcohol use, and 2) is affected acutely and chronically by alcohol use, which cascades to negative effects on sleep and circadian functioning. Quantifying the relationship between alcohol use and ANS functioning in late adolescence is an important first step in understanding other potential implications for prevention and intervention. Accordingly, this project will focus on assessing cardiovascular indices of ANS functioning along with sleep and circadian functioning, and individuals’ affect and cue-reactivity over one month. To accomplish these aims, the study will enlist late adolescent Heavy Drinkers (HD, n = 50; ages 18-20) and age- and sex- matched non-drinking Controls (CON, n = 50) in a 4-week study. Resting-state HRV and BRS will be measured weekly (5x total), and affect ratings will be gathered daily throughout the 4 weeks, while an alcohol cue-reactivity task with simultaneous HRV assessment will be gathered twice (first and last week). The primary aims of the current protocol are to: 1) identify differences in ANS function and cue-reactivity over a month between HD and CON, and 2) quantify the relations between ANS functioning and craving, sleep, affect, and substance use. The candidate will use his training in ANS assessment to test whether HD exhibit differences in ANS functioning, affect, and cue-reactivity related to their alcohol use. Corroborating changes via multiple modalities (e.g., cardiovascular functioning and self-reported measures) will yield a biopsychosocial perspective on the potential underlying mechanisms. The candidate’s long-term goals are to identify markers of risk for substance use in even younger samples and to leverage the malleability of ANS functioning as a potential target of prevention and intervention efforts.