The book provides insight into the association between the personality traits of impulsivity, aggressiveness and self-reported drug and alcohol use. The participants to the study reported in this book were invited to respond to standardised self-report measures of alcohol and drug use, impulsivity and aggressiveness. Although they do not suggest causation, the computed outcomes from the data collected revealed that impulsiveness was significantly and positively correlated with self-reported drug and alcohol use. The association between the various measures of impulsivity and drug and alcohol use persisted, while no relationship was observed between aggressiveness and drug and alcohol use among the participants. In a stepwise linear regression analysis based on the Alcohol Use Disorders Identification Test and the Drug Abuse Screening Test, self-reported drug and alcohol use was highly related to impulsiveness, with the sensation seeking and lack of premeditation components significantly contributing to the prediction. The results are discussed in terms of the need for impulsivity-targeted interventions for individuals who are at a high risk of drug and alcohol misuse.