Social and situational characteristics associated with adolescents' drinking at party and non-party events.

We investigated social and situational characteristics associated with adolescents' drinking at party and non-party events and whether these associations vary by party location (homes versus other locations). Ecological momentary assessment data were obtained over two weekends from 149 adolescents in California (46% female, M age=16.4years), using smartphone surveys administered early and late in the evening and the following morning. We assessed whether, where, and with whom adolescents drank alcohol. Social contexts with more people (RRR=1.05, p≤0.005) and with mixed gender composition (RRR=3.15, p≤0.05) were positively associated with increased risks of alcohol use at parties, but not at non-party events. Conversely, social contexts with friends were positively associated with alcohol use at non-party events (RRR=4.32, p≤0.005), but not at parties. Perceived access to alcohol was associated with increased risks for alcohol use at both party and non-party events, but the association was stronger for alcohol use at parties than non-parties (RRR=1.85, p<0.005 versus 4.01, p≤0.005). Additional analyses showed that contexts with mixed gender composition were positively associated with alcohol use at parties not in homes (RRR=11.29, p≤0.05), and perceptions of getting caught by parents or police were negatively associated with non-party alcohol use in homes (RRR=0.57, p≤0.005). This study identified social-ecological contexts of underage drinking parties, which are high risk settings for heavier drinking and other alcohol-related problems. Findings can inform context-based interventions to target these high-risk settings, whether at homes or other locations.