psychiatry, branch of medicine that concerns the diagnosis and treatment of mental, emotional, and behavioral disorders, including major depression, schizophrenia, and anxiety. Although the Greeks recognized the significance of emotions in mental disorders, medieval thought emphasized demonic influence. From the Middle Ages until the time of the French physician Philippe Pinel (1745-1826), who instituted humanitarian reforms in the care of the mentally ill, there was no organized attempt to study or treat mental abnormalities or to provide decent institutional conditions for the mentally ill. Such 19th-century reformers as Dorothea Dix fought for improved conditions in asylums. The early 20th cent. saw the organization of the mental hygiene movement, dedicated to the prevention of mental disease through guidance clinics and education. Scientists of the period sought underlying causes of mental and nervous disorders. The German psychiatrist Emil Kraepelin was the first to divide psychosis into the two general classifications of manic-depressive psychosis (see bipolar disorder) and schizophrenia. Gradually, some psychiatrists, led by Sigmund Freud, turned to the behavior and emotional history of the patient as clues to the nature of psychoneurosis and psychosis.

Today, a wide variety of treatment strategies are used in psychiatry, to combat many different psychological disorders. Psychiatry may involve physiological or psychological treatment, or a combination of the two. Physiological treatment generally involves the use of drugs influencing neurotransmitter functions in the brain, or electroconvulsive treatment (see electroconvulsive therapy). Psychiatrists are licensed physicians, specially trained to treat patients with mental disorders and to prescribe drugs. In recent years, psychological difficulties have lost much of the stigma they once had, and many people have sought psychiatric help who might have been reluctant to do so in the past.

Branch of medicine concerned with mental disorders. Until the 18th century, mental health problems were considered forms of demonic possession; gradually they came to be seen as illnesses requiring treatment. In the 19th century, research into and classification and treatment of mental illnesses advanced. Sigmund Freud's psychoanalytic theory dominated the field for many years before it was challenged by behavioral and cognitive therapy and humanistic psychology in the mid-20th century. Psychiatrists hold medical degrees and can prescribe drugs and other medical treatments in addition to conducting psychotherapy. The psychiatrist often works as a member of a mental health team that includes clinical psychologists and social workers.

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Branch of medicine concerned with mental, emotional, and behavioral disorders of childhood. It arose as a separate field in the 1920s, largely because of the pioneering work of Anna Freud. Therapy usually involves the family, whose behaviour powerfully affects children's emotional health. Parental death or divorce may affect a child's emotional growth. Child abuse and neglect have also been recognized as significant in childhood disorders. Learning disabilities need to be distinguished from emotional problems—which they can also cause if not diagnosed in time.

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