PROJECT SUMMARY Loneliness is a psychological state arising from a discrepancy between perceived and desired social connection. It is a significant risk factor for health concerns, including problematic alcohol use. Crucially, Latinx individuals in the US experience greater loneliness than non-Latinx White individuals, and those who drink engage in more problematic alcohol use. However, the initial precursors of loneliness and Latinx disparities in loneliness are not well-understood. Moreover, it is unclear if loneliness is a cause of alcohol problems, a consequence of alcohol problems, or a barrier to recovery. The objective of this application is to identify predictors of loneliness in Latinx individuals and explain the link between loneliness and the development of problem drinking in this population. We will evaluate a novel process model that explains loneliness and the development of alcohol problems in Latinx individuals. The ALMA Process Model states that social contextual factors interact with Acculturative Processes to predict Loneliness, Drinking Motives, and Alcohol Problems. The central hypothesis of this research, guided by the ALMA Process Model, is that conflicts between Latinx individuals' cultural orientation and the cultural orientation of those around them contribute to decreases in perceived social connection, leading to loneliness. When feeling lonely, some people increase solitary drinking to cope with loneliness. Drinking to avoid an aversive state will lead people to focus more on that state, exacerbating people's feelings of loneliness. Over time, more solitary drinking will feed back into the experience of loneliness, leading to escalations in problematic alcohol use. Three specific aims will provide structure for evaluating this model: (1) To identify short- term predictors of loneliness and alcohol use in hazardous-drinking Latinx individuals; (2) To determine how loneliness and hazardous drinking lead to the longitudinal development of alcohol problems in Latinx individuals; and (3) To test the reciprocal influence of hazardous drinking and the development of alcohol problems on loneliness trajectories over time in Latinx individuals. Aims will be accomplished using a longitudinal ecological momentary assessment (EMA) “burst” design among 200 hazardous-drinking Latinx individuals from the community. The EMA bursts will occur semi-annually at 0, 6, 12, 18, and 24 months. Data will be collected via self-report, cognitive-behavioral task, wearable alcohol sensor, and geotagging. This project is expected to contribute detailed conceptual information about the mechanisms, processes, and trajectories involved in social connectedness and isolation. By evaluating the innovative ALMA process model, this research will provide a formal explanation for Latinx disparities in loneliness and alcohol problems. Furthermore, this model is expected to have broad impact because it is applicable to many health disparity populations (e.g....