Map of Calpulalpan on psychiatric hospital a public or private institution providing a wide range of diagnostic techniques and treatment to individuals with mental disorders on an inpatient basis. Also called mental hospital. psychiatrist n. a physician who specializes in the diagnosis, treatment, prevention, and study of mental and emotional disorders. In the United States, education for this profession consists of 4 years of premedical training in college; a 4-year course in medical school, the final 2 years of which are spent in clerkships studying with physicians in at least five specialty areas; and a 4-year residency in a hospital or agency approved by the American Medical Association. psychiatry n. the medical specialty concerned with the study, diagnosis, treatment, and prevention of personality, behavioral, and mental disorders, based on the premise that biological causes are at the root of mental and emotional problems. Map of Calpulalpan 2016.