To decide whether a person is physically well or ill is in many cases a task fraught with difficulties. One of the aims of this paper is to analyze some of the problems inherent in such a decision. The opportunity to do so was given in connection with the study of healthy elderly men at the National Institute of Mental Health (Birren et al, 1963).
Another problem closely related to the above-mentioned one is the patient's subjective attitude to health and disease. The patient's own view of the state of his health may differ from the decision reached by the examining doctor. This discrepancy between the patient and the doctor can give rise to hypochondria and other reactions with a strong impact upon adjustment and mental health. In order to understand these reactions in patients under treatment for hypochondria, it is illuminating to know what