[The psyche and cancer]

The question of psychosocial risk factors in cancer is discussed. Selected representative studies from the literature are critically reviewed with emphasis on methodological issues. Indirect and direct risk factors have to be differentiated: indirect factors are defined as psychosocial behavior leading to increased carcinogen exposure, while direct factors are psychosocial stresses inducing psychological reactions that may lead to physical changes in different systems of the body. Thus far, in malignant disease, two direct psychosocial risk factors have been postulated: bereavement and personality. Personality is not discussed. Current investigations of the role of bereavement in cancer risk allow the following conclusion: significant personal loss, i.e. death of a spouse, increases general morbidity and mortality (including cancer) in the bereaved. But loss is not specifically related to cancer incidence. Proneness to depression, however, as a possible psychological reaction to loss, may specifically contribute to the risk of cancer. In the light of recent studies of interactions between psychological state and immune system, this hypothesis appears to be biologically plausible.