The College, Alcohol and Peers Study (CAPS)

The present study will evaluate college students (N=100) from 2- and 4-year colleges/universities between 21-24 years old to assess anxiety, affect, broad social motives (BSM) and peer group influences on drinking and other risk-taking behaviors. This study will employ two sound scientific methods for testing behavior during drinking events (i.e., lab alcohol administration and daily diary) and use novel strategies to compare results of these two methods in the same sample. Using an ad-lib drinking paradigm, students' risk-taking, as measured by the Balloon Analogue Risk Task (BART), will be assessed when alone and during one of two randomly assigned peer group conditions (close friends or new peers). Participants will be allowed to freely drink (within safety limits) with their peer group prior to completing the BART again. These same students will complete daily electronic diaries on four weekends (Thursday - Sunday; total 24 assessments) regarding BSM, motives to drink, peers in their social group, alcohol use and consequences, and if/how their social group changed (e.g., few close friends to large party with many new peers) during the drinking event. Competing hypotheses will be tested such that: 1) anxiety is expected to be a stronger predictor of drinking behavior and greater differences in risk-taking in the new peer condition than close friend condition or 2) BSM is expected to be a stronger predictor of drinking behavior and greater differences in risk-taking in the close friend condition than new peers condition. Results are expected to be replicated in the daily diary reports. Further, this multimethod approach will allow us to evaluate how behavior assessed in the lab predicts naturally occurring behaviors in an uncontrolled setting. For example, the investigators will assess whether greater increases in self-reported risk-taking from baseline to after entering peer groups in the bar lab setting will predict heavier drinking on nights when most drinking companions are close friends reported during daily diary.

Participants (N=100) will be recruited through direct outreach to University of Washington (UW) students via the UW Registrar's directory list, as well as community flyers distributed at colleges in the local area, online advertisements, and word of mouth. Participants will complete screening measures online. Eligible participants will be stratified on sex, age, and past 30-day peak alcohol use and randomly assigned to one of two conditions: close friends (N=50), where participants will recruit two of their existing friends, or new peers (N=50), where participants will drink with two strangers. To ensure at least two eligible friends, those in the close friend group will be asked to provide email and phone numbers of five to seven close friends. Close friends will have to meet the same inclusion and exclusion criteria as target participants and will go through the same procedures as target participants during alcohol administration. For each pair of participants matched on the three strata (age, sex, alcohol use), strangers in the new peer group will be matched to the sex of the close friends of the other matched participant's group.

Participants will be asked not to travel to the bar together to ensure they are not exposed to their peer group before entry to the bar, and must get to the lab without operating any vehicle with wheels (e.g. car, bike). Upon arriving to the lab, all participants and peers will review and sign the consent form, and provide a baseline breath alcohol content (BrAC) reading. Female participants and friends will also be asked to take a urine pregnancy test. Participants and friends will complete baseline measures and the Balloon Analogue Risk Task (BART) individually prior to entry to the bar. Then they will be taught the procedures for the daily diary portion of the study (see below). Participants will join their close friends or new peers in the bar and be given 20 minutes to relax while the researcher prepares the materials. After entering groups but prior to receiving alcohol, participants and peers will complete pre-alcohol measures and the BART. They will then be allowed to order anything from the bar menu for the following hour. Participants and close friends will be allowed to drink freely within limits (BrAC = .12%), for safety. During ad-lib, estimated BAC levels based on age, sex, and weight will be calculated prior to each drink served to ensure the safety of consuming each drink without interrupting social interaction and making the participant's BAC more salient by taking BrAC readings regularly. Participants or close friends whose BAC may exceed .12% will only be served placebo beverages for the remainder of the hour. BrAC readings will be taken at the end of ad-lib, every 10 minutes until peak BrAC is reached and readings are descending, and every 30 minutes thereafter. After ad-lib, participants will complete post-alcohol measures and the BART, then provided entertainment until they reach a BAC below .03%. The full protocol will take approximately 2.5 hours. On average, alcohol metabolizes at a rate of .015% per hour, so a participant who reaches .12% will be in the lab on average 8.5 hours. Once sober, participants and friends will be taken home in a taxi or ride share service (e.g. Uber, Lyft). Close friends will not complete the following daily diary protocols.

Daily diary measures will start on the Thursday following each participant's alcohol administration appointment and be collected for potential drinking events on Thursday, Friday, and Saturday over the following four consecutive weeks. Each day, participants will be notified of surveys by text message at 4 pm and the following morning at 11am (Friday, Saturday, and Sunday) for a total of 24 assessments. Surveys will be available for 2 hours and reminders sent via text 30 minutes before closing. Afternoon assessments take approximately 5 minutes and measure BSM, motives to drink, motives to refrain from drinking, evening plans, and what type of peers they plan to spend the evening with (e.g. close friends, new peers, family, alone). For the daily diary, BSM items have been modified to select experiences which may vary daily (e.g. "making social plans got me excited and energized today) and drinking motives have been modified into a brief prospective measure consistent with modifications used in other studies15. At morning assessments, participants will retrospectively report amount of drinks and other substances consumed, time spent drinking, and consequences experienced while drinking or currently (morning after drinking). Participants will be asked how many times their social group changed during the event defined as the majority of their drinking companions being of a different peer type than before. For instance, a participant may be at a house party with primarily close friends, but someone invites several people the participant does not know well and they are now drinking with mostly new peers. For each peer group reported (up to five groups), participants will report the following characteristics of the group: size (i.e. number of people they had direct contact with), number of drinking companions of each peer type (e.g. close friends, new peers, family), gender composition of the group (same-sex vs. mixed-sex), time spent with and drinks consumed with each group. On non-drinking evenings, participants will report similar information regarding their social groups and other activities. This survey will take approximately 5-7 minutes.

Eligibility Criteria:
Inclusion Criteria:

* currently enrolled in college
* has consumed 3 or more alcoholic drinks in one sitting at least once in the past month
* drinking frequency of once a week

Exclusion Criteria:

* past-month alcohol
* past-month other substance dependence,
* past-month mood disorder
* past-month anxiety disorder
* past-moth suicidal ideation
* excessive alcohol use reaching a BAC greater than .30% in past month
* history of serious medical conditions
* regular use of prescription psychotropic or pain medication
* history of negative reactions to alcohol
* history of treatment for alcohol use disorder
* pregnancy
* nursing