The study requested that 40 police departments in the United States and abroad provide information on their procedures and dispatch codes for managing the mentally ill. Only 28 police departments responded with procedures, and only 11 included dispatch codes even after repeated requests. Characteristics describing mental illness were common in nearly all materials provided. Further, elements of probable cause necessary for police officers to detain a person suspected of being mentally ill appeared to be analogous in procedures submitted by nearly all police departments. Three elements most commonly manifested in police procedures directed at individuals thought to be mentally ill were identified: (1) the individual may intentionally or unintentionally injure self or others; (2) the individual is incapable of attending to his or her basic survival needs; or (3) the individual is senile. Police officers frequently indicated that mentally ill persons were violent and that they could not be reasoned with. Even though they received little or no training in how to deal with the mentally ill, police officers experienced pressure from their departments to resolve incidents involving the mentally ill. Many police departments discouraged the use of physical restraints unless the mentally ill person manifested threatening behavior or such behavior was anticipated. The need for police departments to review existing procedures for mental patient management is emphasized, and improved police procedures are suggested for managing the mentally ill. 88 references