Geriatric psychiatry, also known as geropsychiatry, psychogeriatrics or psychiatry of old age, is a subspecialty of psychiatry dealing with the study, prevention, and treatment of mental disorders in humans with old age. After a 4-year residency in psychiatry, a psychiatrist can complete a one-year fellowship in geriatric psychiatry. As the population ages, particularly in developing countries, this field is becoming more needed. The diagnosis, treatment and management of dementia and depression are two areas of this field.