Identifying individual factors that support and motivate youth to pursue their own (long-term) goals Adolescents and young adults with antisocial behavior and addiction problems struggle to function in a variety of areas, including employment, education, income, social relationships and mental health. Prevention and intervention strategies have been developed to reduce addiction and antisocial behavior, but there are limitations in their effectiveness – for example, we know little about long-term effects and approaches focused on individual differences. Moreover, these strategies often focus only on juvenile delinquency or addiction, while research shows that some of these behaviors stem from the same mechanisms and influence each other. For example, youth use both drugs and delinquent behaviors to reduce negative feelings or increase positive feelings of control. Therefore, it is important to develop strategies that support young people and give them control, based on their motivation and long-term goals. In this project, we examine how effective these strategies are and how they can be optimized using existing knowledge and technologies such as smartphones.