Psychiatrists have always treated aged patients who suffered from mental diseases, whether they were in mental hospitals, in nursing or old folks' homes, in clinics or in the patient's own home.Moreover, psychiatrists described the clinical pictures and the anatomical and histological findings of the important organic psychoses of the senium. One needs only to mention the names of Kraepelin, Alz heimer and Pick. Why then do we now witness, and are even part of, the develop ment of a new sub-specialty called Geri atric Psychiatry?With the many more aged people in our society the number of those requiring psy chiatric care also increases; perhaps even in a greater proportion than the numerical increase of this age group would warrant (6). More beds in mental and general hospitals are occupied by aged psychiatric patients, new and greater clinical facilities such as outpatient and day clinics are being established and more psychiatrists spend more of their time looking after aged patients. Furthermore, the progress in medi cine, anesthesiology and surgery, better care and improved hygienic conditions in mental hospitals and nursing homes has all helped to prolong the life of the mentally-ill aged patient. These factors tend to provide a much better opportunity for long-term studies of the mental diseases occurring in this age group, and these studies have radi cally changed opinion about the natural history of these diseases. These disorders are not confined to the so-called organic psychoses of the senium but are varied as to their symptomatology, their course and outcome, and it is now recognized that some are treatable and even curable. This imposes on the psychiatrist the responsible task of studying his aged patients most carefully in order to arrive at a correct ^Associate Professor of Psychiatry and Director of the