BackgroundThe aim of this study was to determine the association between physical and psychiatric morbidity among general practice patients and to explore the influence of possible intervening variables.MethodPhysical and psychiatric morbidity in 1620 consecutive patients attending their general practitioner (GP) was assessed using a two-stage design. Ninety-four per cent of the patients (n=1523) were successfully screened using the General Health Questionnaire (GHQ–12); 428 of the 602 patients (71%) eligible for the second stage were interviewed using the Composite International Diagnostic Instrument adapted for use in primary health care (CIDI–PHC), the Brief Disability Questionnaire (BDQ) and the Groningen Social Disability Schedule (GSDS) to assess psychiatric, physical and social status. Assessments of physical and psychiatric morbidity were also obtained from the patients' GPs.ResultsThere was a significant association between physical and psychiatric morbidity, although patients with four symptoms or less of physical illness were no more likely to be psychiatric cases than those with none. The association was accounted for by patients at the severe end of the physical continuum with five or more medically explained somatic symptoms: these were twice as likely to be psychiatric cases as those with no such symptoms. Female gender, social disability and physical disability were all significantly more likely to be associated with psychiatric disorder, whether measured by GP or research interview; and these relationships remained after the data were corrected for age differences.ConclusionsPatients in general practice with moderate to severe physical morbidity are at increased risk of developing psychiatric illness, and when medical illness is present, psychiatric symptoms are more severe. As physical and psychiatric comorbidity is relatively common in general practice, the specific needs of these patients should receive greater attention.