Psychological factors in illness and recovery.

To review evidence that psychological factors affect the course of physical illness three areas are examined: epidemiological evidence showing the levels of psychiatric disturbance co-morbid with physical illness; health services research showing the burden of disease and care associated with this co-morbidity; randomised, controlled trials of psychological interventions in cancer, myocardial infarction and irritable bowel syndrome. There is substantial psychiatric co-morbidity with physical illness which is associated with increased disability, mortality and utilisation of health-care resources (primary care visits, hospitalization, length of hospital stay, cost). A small number of controlled intervention studies have shown the efficacy of psychological interventions to prolong survival in cancer and myocardial infarction, and to improve symptomatology in irritable bowel syndrome and other chronic somatizing conditions. Psychological factors do significantly affect outcomes of physical illness. The role of psychological treatments, alongside somatic therapies, needs further study.