The purpose of this multi-site RCT is to determine the effectiveness of the MAC group intervention on reducing psychotic disorder symptomatology (primary outcome) as well as promoting quality of life, critical skills for recovery and decreasing mental health service utilization (secondary outcomes) for transitional aged youth (16-25 years old) experiencing early psychosis. This study will be run across five southern Ontario Early Psychosis Intervention (EPI) sites with Prevention and Early Intervention Program for Psychoses (PEPP) at London Health Sciences Centre (LHSC) being the lead site. We aim to recruit 24 participants from each the five EPI programs for the study (total n=120 participants). Participants will be randomized into Group-A (n = 12; immediate treatment intervention group) or Group-B (n = 12; delayed treatment intervention group). Group-A will receive the MAC intervention at the onset of the study, while Group-B will receive treatment as usual (TAU). Group-B will have the option of receiving the MAC intervention approximately 6 months after the onset of the study. At all times during this study, participants who are receiving the MAC intervention will also be able to continue receiving TAU. Both groups will be assessed with a battery of quantitative measures at baseline (T1), three months later (i.e., immediately post-MAC intervention) (T2), and again three months post-MAC intervention (T3). The measures include interview assessments of psychotic disorder symptoms, and self-report measures of affect, self-esteem, quality of life, coping strategies, assertiveness, social functioning, mindfulness and cognitive skills. In addition, healthcare utilization records for the 6 months preceding MAC intervention onset and for the 6 month duration of the study (3 month MAC intervention + 3 month post-MAC intervention follow-up period) will be collected. Researchers conducting symptom assessment interviews and data analysis will be blinded to the group membership of participants. Based on the pilot study at PEPP-LHSC, and based on previous findings of Mindfulness Based Interventions for psychoses in the literature, we are expecting that participation in the MAC intervention will result in improvement in the following areas: quality of life, measures of recovery (self-esteem, perceived recovery), perceived coping, assertiveness, social functioning, mindfulness and cognitive skills, and a reduction in healthcare service utilization (e.g., emergency room visits, inpatient admissions/length of hospitalization).