Predictors of Aggressive Behavior While under the Influence of Illicit Drugs among Young Adult Methamphetamine Users.

BACKGROUND: Prior research indicates that patterns of combined alcohol and methamphetamine use may be associated with experiencing subjective feelings of aggression or hostility during methamphetamine use episodes.

OBJECTIVES: This study examines whether subjective effects of methamphetamine use (i.e., aggression or hostility and paranoia) are associated with aggressive behavior while under the influence of any illicit drugs, controlling for combined alcohol and methamphetamine use and a number of other potential predictors.

METHODS: Data from a population-based sample of Australian young adult methamphetamine users (n = 101) collected in 2010 was analyzed. A prediction model of aggressive behavior under the influence of illicit drugs was developed using penalized maximum likelihood logistic regression.

RESULTS: Over one-third (34.7%) of methamphetamine users had engaged in verbal and/or physical aggression under the influence of illicit drugs in the last 12 months. In the prediction model, recurrent feelings of aggression or hostility attributed to methamphetamine use (≥3 times in the last 12 months) were associated with aggressive behavior (adjusted odds ratio 4.95, 95% confidence interval 1.67, 14.69). This association was independent of methamphetamine-attributed paranoia, combined alcohol and methamphetamine use, methamphetamine, ecstasy, cocaine, and cannabis use patterns, heavy episodic drinking, gender, and age. No association was found for combined alcohol and methamphetamine use.

CONCLUSIONS: These findings indicate a link between methamphetamine-related subjective feelings of aggression or hostility and self-reported aggressive behavior while under the influence of illicit drugs. This suggests that subjective feelings of aggression or hostility may distinguish those who are involved in aggression from other methamphetamine users.