Mechanisms of Risky Alcohol Use in Young Adults: Linking Sleep to Reward- and Stress-Related Brain Function

Inclusion Criteria:

1. 18-24 years of age;

2. NIAAA criteria for past-month high-risk drinking (i.e., ≥ 4 drinks/day or ≥ 8/weekfor women, ≥ 5 drinks/day or ≥ 15/week for men);

3. short and late sleep (weekday sleep duration ≤ 7 hours and bedtime ≥ 24:00 (midnight); n=60) or long and early sleep (weekday sleep duration ≥ 7 hours andbedtime ≤ 24:00 (midnight); n=30), which will be determined with the MunichChronotype Questionnaire;

4. at least moderate lifetime exposure to stressors (≥ 2 events on the 20-item AdultStress and Adversity Inventory-Screener);

5. not currently in high school; and

6. English language fluency.

Exclusion Criteria:

1. Severe alcohol use disorder (AUD) and/or substance use disorder (SUD), defined as ≥6AUD/SUD criteria in the Diagnostic and Statistical Manual-5;

2. acute alcohol intoxication on the days of the laboratory post-intensive visits,operationalized as a blood alcohol concentration of .02 or higher duringBreathalyzer saliva screen;

3. current sleep disorders other than insomnia, delayed sleep phase disorder, orhypersomnia;

4. lifetime diagnosis of bipolar or schizophrenia spectrum disorder;

5. urgent suicide risk, defined by moderate/severe risk as per Columbia SuicideSeverity Rating (CSSR) Community Card, and clinician determination that current riskrequires immediate action, precluding engagement in study;

6. certain medical conditions (e.g., serious neurological disorder, heart failure orserious trouble, history of head injury with unconsciousness > 5 minutes);

7. conditions that are contraindicated for MRI (e.g., ferrous metal in the body);

8. positive screen for participant-reported eye disease, epilepsy, or photosensitizingmedications that are contraindicated during the manipulation condition when brightlight is administered (e.g., psychiatric neuroleptic drugs [e.g., phenothiazine],psoralen drugs, antiarrhythmic drugs [e.g., amiodarone], antimalarial andantirheumatic drugs, porphyrin drugs used in photodynamic treatment of skindiseases);

9. use of melatonin if participant is not willing to discontinue use for the durationof the study.

We will schedule around (i.e., delay appointments as needed) to avoid the timeframe of the following events:

1. travel across two or more time zones within the month prior to the overnight studyvisits.

2. begin/end a prescribed medication within 2 months of the observational study;

3. medication dose changes within the timeframe calculated as 5x the drug's half-life [the time to reach pharmacokinetic steady-state] before the initiation of theobservational or experimental studies;

4. participant-anticipated changes in prescribed medications or medication dosingduring the observational or experimental studies.

Participants with positive breathalyzer screen (blood alcohol level > .02) will be rescheduled for an alternative overnight visit date. Participants excluded for suicide risk may become eligible for the study when the risk has dissipated. We will reschedule participants who have current symptoms of an airborne infectious illness (e.g., COVID).