Results of the study suggest that developmental factors are important contributors to violence. Anger, frustration, and situational opportunities were short-term motivating influences for violence. For many of the study sample participants that engaged in violence, chronic methamphetamine use had a disorganizing effect on their cognitive functions. The most significant pharmacologic determinants of the methamphetamine-violence link are the dose and the chronic exposure to the drug. At acute low doses, methamphetamine produces cognitive and mood alterations, but tends not to increase offensive-aggressive behavior. With increasing dose and long-term use, methamphetamine users tend to display psychological and physical deterioration, as well as changes in their social behavior. Many people behave aggressively when under the influence of drugs. It is apparent from these findings that methamphetamine use is a risk factor for violence. The findings have important implications for interventions aimed at reducing methamphetamine use and violence. The results suggest the importance of improving collaborative efforts across multiple intervention systems. Empirical evidence concerning patterns of violence is sparse, particularly its relationship to violence among young adults. This study was designed to explore the relationship among methamphetamine use and violence among young adults. The study sample included 55 respondents in drug treatment and 51 active community methamphetamine users. The majority of respondents were male Hispanic high school graduates in their 20s. Figure, tables, references