Ultimately some find themselves incarcerated, not by the mental health community, but by the judicial system. Trauma at birth, coupled with chronic drug use by my nephew's biological mother conspired to produce severe emotional disorders. Despite the help and attention provided by his parents, when he reached adolescence it was clear that his emotional development and maturity would never keep pace with his physical growth. Now that my nephew is an adult, his parents are in a constant struggle to secure the right environment for their son. He is too big and strong to live with his parents.
Confinement is counterproductive, disrupting rather than nurturing familial and other relationships.
On the other hand, he is does not have the social skills and habits necessary to live entirely on his own. It would be far cheaper to provide an environment sufficiently open to allow my nephew to participate in the community, but adequately supervised so that he remains on necessary medication and has regular place to sleep and eat, than to incarcerate him on some petty crime committed as part of delusion or confusion. Unless one believes that there is no such thing as personal responsibility, there is a dichotomy in mental illness. There is the mental illness that is largely organic in nature and at least potentially treatable by drug or other therapy. There is the emotional illness induced from bad habits or difficulty coping with emotional trauma.