A collagen, or connective tissue, disease of unknown cause affecting small blood vessels in various organs of the body, including the brain; classified by the American Psychiatric Association (1952) as a chronic brain syndrome associated with diseases of unknown or uncertain cause.Approximately 85 per cent of all cases occur in women. The onset is usually in childhood, but the disease is frequently not recognized until adolescence or early adult life. The early signs are easy fatigability, fever, and migratory joint pains that resemble rheumatic fever or rheumatoid arthritis. In many cases there is a butterfly rash on the bridge of the nose or cheeks. A positive diagnosis is made by identifying certain cells (LE cells) in blood smears.Mental symptoms occur in the majority of cases. They usually begin with anxiety and exaggeration of previous personality tendencies. Later on about half the patients become delirious or develop schizophrenic reactions, usually of the paranoid type. Phobic and depressive reactions are also found in some cases. These psychological symptoms are believed by some investigators to be due to the use of the steroids cortisone or ACTH, which are the standard treatment for the disease. Others, however, believe they are the direct result of the disease process itself, especially since brain lesions are usually found at autopsy. Treatment requires the collaboration of a psychiatrist with the internist. Remissions sometimes occur, but the disease is usually fatal. See BRAIN DISORDERS.