Psychiatric hospitals, also known as mental health hospitals or behavioral health hospitals, are hospitals or wards specializing in the treatment of severe mental disorders, such as schizophrenia, bipolar disorder, eating disorders, dissociative identity disorder, major depressive disorder and many others. 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 containment of patients who need routine assistance, treatment, or a specialized and controlled environment due to a psychiatric disorder. Patients often choose voluntary commitment, but those whom psychiatrists believe to pose significant danger to themselves or others may be subject to involuntary commitment and involuntary treatment.[1][2] Psychiatric hospitals may also be called psychiatric wards/units (or psych wards/units) when they are a subunit of a regular hospital.