Disorders with physical symptoms, but having a psychological cause. It is known that psychological factors can to a large extent affect the course of an illness, any complications and the speed of recovery. Hereditary factors are significant: some people react excessively with part of the autonomic nervous system to emotional pressure. The patient’s circumstances also play an important part, as does the structure of his personality. It is not known for certain how body and mind interact. The most important psychosomatic disorders, or disorders with a psychosomatic component, include stomach ulcer, ulcerative colitis, and other intestinal inflammation, asthma, ‘essential’ high blood pressure, rheumatoid arthritis and migraine. People with a psychosomatic illness often make use of defence mechanisms to suppress conflicts and aggression. It is possible that psychosomatic disorders are themselves such a mechanism, and related to a conversion symptom. The physical aspect of the illness must of course be treated, and a change in lifestyle or psychotherapy can be helpful. It is usually necessary for the patient to accept psychological treatment.