Forensic mental health is a specialized area in the mental health system that deals with the intersection between mental illness and the law. It encompasses the interface between law and psychiatry. Forensic mental health services provide assessment and treatment of people with a mental illness who have offended, or are at risk of offending. People in the criminal justice system have significantly higher rates of mental illness than people in the general community. Forensic mental health clinicians may become involved when prisoners need inpatient treatment, require assessment or treatment of a mental illness, or are accused of crimes but are considered unfit to plead because of their mental impairment.

Forensic mental health spans criminal and civil legal matters and the regulation of mental health delivery. In the criminal legal sphere, forensic mental health includes the treatment and assessment of individuals involved in the criminal legal system who have a mental illness. In the civil sphere, forensic mental health has even broader applications, including involuntary commitment and treatment, child custody evaluations, assessments of various competencies, fitness for duty evaluations, and evaluations related to psychological injury claims. Forensic aspects of the regulation of mental health encompass understanding and appraisal of mental health laws and their impact on the delivery of care to persons with mental illness.

Forensic mental health clinicians, including forensic psychiatrists, psychologists, and social workers, receive specialized training in the procedures and processes of the legal system and in the administration of mental health services (e.g., assessments, treatment) that are aligned with their respective scopes of practice. They ask empirical questions that are relevant to the courts. The goal of forensic mental health services is to provide recovery-focused treatment with the aim of successful rehabilitation and a safer community.