Our data strongly suggest that collaborations between the criminal justice system, the mental health system, and the advocacy community plus essential services reduce the inappropriate use of U.S. jails to house persons with acute symptoms of mental illness.

In this study, we sampled sworn police officers from three law enforcement agencies (n=452), each of which had different system responses to mentally ill people in crisis. One department relies on field assistance from a mobile mental health crisis team, a second has a team of officers specially trained in crisis intervention and management of mentally ill people in crisis, and a third has a team of in‐house social workers to assist in responding to calls. Calls involving mentally ill people in crisis appear to be frequent and are perceived by most of the officers to pose a significant problem for the department; however, most officers reported feeling well prepared to handle these calls. Generally, officers from the jurisdiction with a specialized team of officers rated their program as being highly effective in meeting the needs of mentally ill people in crisis, keeping mentally ill people out of jail, minimizing the amount of time officers spend on these calls, and maintaining community safety. Officers from departments relying on a mobile crisis unit (MCU) and on police‐based social workers both rated their programs as being moderately effective on each of these dimensions except for minimizing officer time on these calls where the MCU had significantly lower ratings. © 1998 John Wiley & Sons, Ltd.

Police departments in the 194 U.S. cities with a population of 100,000 or more were surveyed in 1996 to identify strategies they used to obtain input from the mental health system about dealing with mentally ill persons. A total of 174 departments responded (90 percent). Ninety-six departments had no specialized response for dealing with mentally ill persons. Among the 78 departments with special programs, three basic strategies were found: a police-based specialized police response, a police-based specialized mental health response, and a mental-health-based specialized mental health response. At least two-thirds of all departments, even those with no specialized response program, rated themselves as moderately or very effective in dealing with mentally ill persons in crisis.

For nearly 30 years jail diversion programs have had wide support as a way to prevent people with mental illnesses and substance use disorders from unnecessarily entering the criminal justice system by providing more appropriate community-based treatment. Although these programs have had wide support, very few systematic outcomes studies have examined their effectiveness. This paper discusses findings on rates of incarceration of persons with serious mental illness and co-occurring substance use disorders in U.S. jails, summarizes recently completed research on jail diversion programs, and describes a three-year research initiative begun in 1997 by the Substance Abuse and Mental Health Services Administration that uses a standardized protocol to examine the characteristics and outcomes of various types of jail diversion programs in nine sites throughout the U.S.