Involuntarily admitted patients were recruited from the admissions unit of a regional State psychiatric hospital and three other inpatient facilities. Eligibility criteria for participation were 18 years old or older, diagnosis of a psychotic disorder or major mood disorder, duration of disorder for 1 year or more, North Carolina Functional Assessment Scale score of 90 or greater (serious impairment), intensive treatment within the past 2 years, resident of one of nine counties participating in the study, awaiting a period of court-ordered outpatient commitment, and permission by the treatment team to approach the patient. Extensive face-to-face interviews were conducted with 331 people with severe mental disorders. Measures focused on medication noncompliance, use of services, co- occurring substance use, violent behavior, and arrest and police encounters. The study found that 20 percent of the sample reported being arrested or picked up by police for a crime at some time in the 4-month period before their hospital admission, most commonly for alcohol or drug offenses, or crimes of public disorder (e.g., loitering or trespassing). Risk of a police encounter was significantly related to recent use of alcohol or drugs and recent violent behavior; however, substance use was apparently related to police encounters only when medication noncompliance was also involved. Thus, violent behavior and the combination of medication noncompliance and substance use significantly increased the odds of a police encounter. 2 tables, 4 notes, and 34 references