Introduction Emerging evidence indicates an association between mental illness and low-intensity of physical healthcare. To test this, we compared rates of visits to a general practitioner (GP) between mental health clients (MHCs) and non-MHCs.

Methods Population-based retrospective cohort study of 204 727 MHCs and 294 076 matched non-MHCs in Western Australia from 1 January 1990 to 30 June 2006, based on linked records of the use of mental health services, hospital admissions, Medicare claims for GP and specialist services, electoral roll registration and deaths. Adjusted rate ratios (ARRs) for the number of visits to GPs by MHCs relative to non-MHCs, and for different categories of mental disorders.

Results Relative to non-MHCS, the ARR of visits to GPs by MHCs was 1.622 (95% CI 1.613 to 1.631) overall, and was elevated in each separate category of mental illness. ARRs were highest for alcohol/drug disorders, schizophrenia and affective psychoses (2.404, 1.834 and 1.798, respectively). The results were not changed by location (metropolitan, rural or remote addresses). However, the 4% of MHCs with no fixed address had a very low ARR of visits to GPs (0.058; 95% CI 0.057 to 0.060).

Conclusion MHCs visit GPs substantially more often than non-MHCs, with the exception of those with no fixed address who seldom see a GP at all.