It is argued that intoxication disrupts social interactions between people. As emergent affiliative behaviors, such as line formation, that serve to increase flow and minimize invasions to personal space, and therefore goal attainment, are a product of individual level interactions, it is argued that intoxication increases individuals levels of stress and therefore aggression. The self-propelled particle (SPP) model is presented to understand why intoxicated crowds display greater levels of violence as crowd density increases. The model is illustrated by a particle model of crowd behavior. Models of crowd behavior, derived from particle physics, have been successfully developed to account for collective emergent features in both human and nonhuman organisms through modeling individual level interactions. Aggressive behavior is more frequent in drunken crowds compared to sober crowds. However, there exists no predictive theory on why intoxicated crowds should display greater levels of violence as crowd density increases. This paper presents such a model. Figures, table, and references