Physical disorders associated with mental illness. A register investigation.

On the basis of nationwide patient register data the diagnostic pattern of the medical admissions of a general population (17-49 year-olds; N = 30427) during an 8-year period was studied by comparing those individuals who had been admitted to the psychiatric department (i.e. psychiatric patients) with those individuals who had not. The results suggest that the high utilization of medical admissions by psychiatric patients could not be explained simply by coincident chronic physical illness or particular types of physical disease including the somatic complications of mental disorders. It is more likely to be attributable to other factors such as an increased general susceptibility to physical illness, different forms of illness behaviour, and the process of somatization.