Programs offered in special units of general acute care hospitals that provide diagnostic and treatment services for adults who have acute psychiatric disorders, require hospitalization for maximum benefit, and who may be a threat to themselves, to their families or to others if left in the community or placed in a less restrictive treatment setting. Services may include a comprehensive evaluation; 24-hour care in a supportive, therapeutic environment; counseling for the patient and family; adjunctive therapies as needed; medication, if required; and an aftercare program following discharge.

Disorders that are characterized by persistent feelings of apprehension, worry, uneasiness or dread the source of which is frequently nonspecific or unknown to the individual which may be accompanied by restlessness, irritability, lack of concentration, difficulty sleeping, increased heart rate, shortness of breath and other physiological symptoms.

A disorder that is marked by episodes of psychotic depression, excessive well-being or mixed episodes alternating with longer periods of relative normalcy. Manic episodes are characterized by elevated, expansive or irritable moods which are accompanied by hyperactivity, pressure of speech, flight of ideas, inflated self-esteem, decreased need for sleep, distractibility and excessive involvement in activities that have a high potential for painful consequences, which is not recognized. The depressive episodes are characterized by loss of interest or pleasure in all or almost all usual activities and pastimes, appetite disturbance, change in weight, sleep disturbance, psychomotor agitation or retardation, decreased energy, feelings of worthlessness or guilt, difficulty concentrating or thinking and thoughts of death or suicide or suicide attempts. During mixed episodes, the individual experiences rapidly alternating moods of sadness, irritability and euphoria.

A disorder that is characterized by one or more major depressive episodes but no manic episodes. Depressive episodes are characterized by loss of interest or pleasure in all or almost all usual activities and pastimes, appetite disturbance, change in weight, sleep disturbance, psychomotor agitation or retardation, decreased energy, feelings of worthlessness or guilt, difficulty concentrating or thinking and thoughts of death or suicide or suicide attempts.

Any of a group of disorders that are characterized by onset before age 45, deterioration from a previous level of functioning in areas such as work, social relations or self-care, and at least one of the following during a phase of the illness: bizarre delusions such as delusions of being controlled, thought broadcasting, thought insertion or thought withdrawal; somatic, grandiose, religious or nihilistic delusions; delusions with jealous or persecutory content accompanied by hallucinations of any type; auditory hallucinations; or incoherence associated with a blunted, flat or inappropriate affect, delusions or hallucinations, or catatonic or other grossly disorganized behavior.