A forensic patient is a person with mental illness or intellectual disability who is in custody or on a legal hold by law enforcement or corrections officials. They are patients subjected to a criminal law trial procedure or cases for whom a court decision has been taken at the time of treatment. Forensic mental health services provide assessment and treatment of people with a mental illness who have offended or are at risk of offending. Forensic patients can be categorized into pre-trial and post-trial cases. 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 psychiatric care treats mentally disordered offenders, who mainly suffer from psychotic disorders, although co-morbidities such as substance use disorders, eating disorders, and trauma-related disorders are also common.