AIM: The relationship between family behaviour and depression in adolescents at clinical high risk (CHR) for psychosis remains understudied despite high rates of depression in this population. This study examines the relationship between family problem-solving behaviours and depression in CHR adolescents and the impact of family interventions targeting subthreshold symptoms of psychosis on reducing symptoms of depression over 2-years. METHODS: Participants were a subset of the North American Prodrome Longitudinal Study who were randomized to 6-months of family focused therapy for individuals at CHR or family psychoeducational treatment. We evaluated the relationship between communication during family conflict discussion and adolescents symptoms of depression before treatment. At follow-up assessments the family treatment groups were compared on depression. Finally, we compared those in family treatment with matched controls. RESULTS: Adolescents constructive communication was associated with less severe symptoms of depression before treatment. Symptoms of depression improved for adolescents in both family treatment groups. However, there were no significant group by treatment interactions. When adolescents who participated in either type of family intervention were compared to CHR adolescent controls, symptoms of depression improved for adolescents in treatment and control groups, but there were no significant time by treatment interactions. CONCLUSIONS: The communication skills of CHR adolescents are related to both depression and their parents communication skills pre-treatment. However, reductions in depression over the course of the treatment trial cannot be attributed to family treatment. It is imperative to incorporate interventions that directly target depression into future family treatment studies.