RecruitingBehavioural interventionA Randomized Controlled Trial Testing the Effect of the Youth Mindful Awareness Program on Negative Affect (YMAP2).The goal of this randomized clinical trial is to compare the effects of an online mindfulness program to an active supportive comparison condition and a no-intervention control group on reducing and preventing mood and anxiety symptoms in at-risk youth. Youth who are high on trait negative affect will be randomized to one of the three conditions. The primary outcomes of interest are reductions in momentary negative affect and internalizing problems in adolescents ages 12 to 17 years old. All participants will be evaluated prior to being randomized, after the 9-session intervention period, and at a 6-month follow-up. The first hypothesis is that the mindfulness intervention will predict decreases in stressor-reactive momentary negative affect and internalizing symptoms. The second hypothesis is that changes in momentary negative affect will partially account for the effects of the mindfulness intervention on internalizing symptoms.