Assertive community treatment (ACT) is an intensive and highly integrated approach for community mental health service delivery. ACT teams serve individuals with the most serious forms of mental illness, predominantly but not exclusively the schizophrenia spectrum disorders. ACT service recipients may also have diagnostic profiles that include features typically found in other DSM-5 categories (for example, bipolar, depressive, anxiety, and personality disorders, among others). Many have histories of frequent psychiatric hospitalization, substance abuse, victimization and trauma, arrests and incarceration, homelessness, and additional significant challenges. The symptoms and complications of their mental illnesses have led to serious functioning difficulties in several areas of life, often including work, social relationships, residential independence, money management, and physical health and wellness. By the time they start receiving ACT services, they are likely to have experienced failure, discrimination, and stigmatization, and their hope for the future is likely to be quite low.