Psychiatry is the branch of medicine concerned with the study of mental illness. It is has two major branches: one is psychotherapy, the application of psychological techniques to the treatment of mental illnesses where a physiological origin is wither unknown or does not exist; the other, medical therapy, where attack is made on either the organic source of the disease or, at least, on its physical or behavioral symptoms. (Psychotherapy and medical therapy are often used in tandem.) As a rule of thumb, the former deals with neuroses, the latter with psychosis. (See also psychology.)
Drugs are perhaps the most widely used tools of psychiatry. Many emotional and other disturbances can be simply treated with tranquilizers. A major area of success for drug therapy is alcoholism. Other major areas of success are drug addiction and the amelioration of the effects of epilepsy.