Contacts related to mental illness and substance abuse in primary health care: a cross-sectional study comparing patients' use of daytime versus out-of-hours primary care in Norway.

OBJECTIVE: To investigate prevalence, diagnostic patterns, and parallel use of daytime versus out-of-hours primary health care in a defined population (n = 23,607) in relation to mental illness including substance misuse.
DESIGN: Cross-sectional observational study.
SETTING: A Norwegian rural general practice cooperative providing out-of-hours care (i.e. casualty clinic) and regular general practitioners' daytime practices (i.e. rGP surgeries) in the same catchment area.
SUBJECTS: Patients seeking medical care during daytime and out-of-hours in 2006. MAIN OUTCOME MEASURES: Patients' diagnoses, age, gender, time of contact, and parallel use of the two services.
RESULTS: Diagnoses related to mental illness were given in 2.2% (n = 265) of encounters at the casualty clinic and in 8.9% (n = 5799) of encounters at rGP surgeries. Proportions of diagnoses related to suicidal behaviour, substance misuse, or psychosis were twice as large at the casualty clinic than at rGP surgeries. More visits to the casualty clinic occurred in months with fewer visits to rGP surgeries. Most patients with a diagnosis related to mental illness at the casualty clinic had been in contact with their rGP during the study period.
CONCLUSION: Psychiatric illness and substance misuse have lower presentation rates at casualty clinics than at rGP surgeries. The distribution of psychiatric diagnoses differs between the services, and more serious mental illness is presented out-of-hours. The casualty clinic seems to be an important complement to other medical services for some patients with recognized mental problems.