Psychiatric hospitals, also known as mental hospitals and psychiatric wards (""psych"" wards) when they are a sub-unit of a regular hospital, are hospitals or wards specializing in the treatment of serious mental disorders, such as clinical depression, schizophrenia, and bipolar disorder. Psychiatric hospitals vary widely in their size and grading. Some hospitals may specialize only in short-term or outpatient therapy for low-risk patients. Others may specialize in the temporary or permanent care of residents who, as a result of a psychological disorder, require routine assistance, treatment, or a specialized and controlled environment. Patients are often admitted on a voluntary basis, but people whom psychiatrists believe may pose a significant danger to themselves or others may be subject to involuntary commitment.Modern psychiatric hospitals evolved from, and eventually replaced the older lunatic asylums.The treatment of inmates in early lunatic asylums was sometimes brutal and focused on containment and restraint. With successive waves of reform, and the introduction of effective evidence-based treatments, modern psychiatric hospitals provide a primary emphasis on treatment, and attempt where possible to help patients control their own lives in the outside world, with the use of a combination of psychiatric drugs and psychotherapy.A crisis stabilization unit is in effect an emergency room for psychiatry, frequently dealing with suicidal, violent, or otherwise critical individuals. Open units are psychiatric units that are not as secure as crisis stabilization units. Another type of psychiatric hospital is medium term, which provides care lasting several weeks. In the United Kingdom, both crisis admissions and medium term care is usually provided on acute admissions wards. Juvenile or adolescent wards are sections of psychiatric hospitals or psychiatric wards set aside for children and/or adolescents with mental illness. Long-term care facilities have the goal of treatment and rehabilitation back into society within a short time-frame (two or three years). Another institution for the mentally ill is a community-based halfway house.Critics such as American psychiatrist Thomas Szasz have insisted that psychiatric hospitals are like prisons, not proper hospitals, and that psychiatrists who subject others to coercion function as judges and jailers, not physicians. The French historian Michel Foucault is widely known for his comprehensive critique of the use and abuse of the mental hospital system in Madness and Civilization.Franco Basaglia, a leading Italian psychiatrist who inspired and was the architect of the psychiatric reform in Italy, also defined the mental hospital as an oppressive, locked and total institution in which prison-like, punitive rules are applied.