Current rates of excessive alcohol use and abuse among young adults are recognized as a major problem by scholars across a wide variety of fields. Here, I take a social psychological approach to understanding why individuals drink to excess, examining the unique role that a specific form of social isolation called existential isolation (feeling alone in one’s experiences of the world; Yalom, 1980; Pinel, Long, Murdoch, & Helm, 2017) may play in predicting alcohol use and abuse. The relationship between existential isolation and alcohol use is explored using both correlational and cross-lagged designs. Results indicate that existential isolation predicts alcohol use above and beyond a more traditional measure of social isolation, though not in the hypothesized direction (i.e. social isolation is associated with more alcohol use, whereas existential isolation is associated with less). Further, negative emotional symptoms (depression, anxiety, and stress) and racial identity emerged as significant moderators of this effect. Exploratory analyses considering a reversal of the hypothesized causal direction (i.e. alcohol use now predicting feelings of existential isolation) revealed a significant two-way interaction between current and lifetime alcohol use and a significant three-way interaction between current alcohol use, desire for existential connection, and motivations to use alcohol for social purposes. Implications of these general findings are discussed, including that 1) they identify a seemingly positive outcome of drinking that may play a role in perpetuating problematic alcohol use, and 2) conversely, they may illustrate a “dark side of sobriety.” This research serves as a first step into distinguishing between aspects of social isolation in the realm of alcohol use and abuse. Future research is necessary in order to identify the mechanisms underlying this effect and inform the development of more effective alcohol-related interventions.