This document provides information on mental illness prevalence, symptoms of mental disorders, interactions with individuals in crisis, and self-care for professionals. Some key points: - Nearly 1 in 5 American adults lives with a mental illness such as major depression, anxiety disorders, or substance abuse disorders. - People with mental illnesses account for about 25% of police-involved deaths. In 2015, 251 of the 991 people shot and killed by police were known to have a mental illness. - Mental health disorders are highly prevalent in incarcerated populations, with over 70% of youth in the juvenile justice system having at least one condition.