The overall aim of this pilot study is to conduct a preliminary trial to evaluate the acceptability and feasibility of adding a transdiagnostic, emotion-focused group intervention (the Unified Protocol, UP) to treatment as usual (TAU) in a comprehensive outpatient program for adolescents and young adults with substance use disorders and emotional distress. Only patients seeking services or engaged in care at an existing outpatient program at MGH (the Addiction Recovery Management Service) are eligible for participation.