This resource was approved by the SMI Adviser clinical expert team for inclusion in the knowledge base.
One in five adults in the United States has a mental illness. Mental illness is a broad term, and types and severity of mental illness vary. About 4 percent of the population has a mental illness that limits their life activities, known as serious mental illness. Over their lifetimes, about 3 percent of people will have a serious mental illness that includes psychosis. Psychosis can happen at any age, but it often begins when people are between ages 15 to 30.1 This means that about 100,000 young people will have an early episode of psychosis each year.