MARS (Motivating Adolescents to Reduce Sexual risk) is an intervention targeted at reducing adolescent risky sexual behavior, particularly in contexts where alcohol or marijuana use may be involved. An evaluation of the MARS intervention showed that it resulted in decreased incident sexually transmitted infections one year after delivery. This one-session, two-hour intervention is appropriate for community based settings including juvenile justice centers for use with high risk adolescents. The MARS intervention is delivered in a motivational enhancement therapy format. The approach for this intervention is grounded in the assumption that the responsibility and capability for change exist within the participant. The role of the intervention leader is to create an environment that will enhance the participant’s inherent motivation for, commitment to, and movement towards behavior change. The intervention involves group discussion and exercises focused on establishing a condom language, talking about condom use, provision of norms, self-affirmation, high risk situations, and how one might change, along with video review, interactive games, and skills building. The intervention is led by a Masters or PhD level therapist. Groups should be kept small and capped at 6 to 8 participants, and the age range of participants in the group should be restricted to two years (for example, 14-16 or 16-18) in order to keep the range of experiences similar. Although MARS is appropriate for all genders, if possible adolescent groups should be kept single-sex. MARS has been evaluated in a cluster randomized controlled trial. Data was collected at pre-test and immediate post-test as well as 3, 6, 9, and 12 months post-intervention. The intervention was effective at reducing STI incidence. Participants had lower incidence of STI at follow-up than participants who received comparison interventions with only sexual risk or sexual risk and alcohol content, as opposed to sexual risk, alcohol, and cannabis content. Click here to view more detailed information on this program.