The aim of the study was to investigate the course of psychiatric illness in primary care patients. A 12-month follow-up study was conducted using a subsample of 93 patients, assessed by interviewing with the aid of the Present State Examination (PSE), from an original cohort of 388 primary care patients in a Swedish health district. The relationships of the course of illness to psychosocial stress, perceived health, utilization of care and health insurance, and patient satisfaction with primary health care services were investigated.The results showed that at index contact, 32.1 % of the follow-up sample were psychiatric cases in need of treatment according to the screening procedure with the Hopkins Symptom Check List (HSCL-25). The continuing cases constituted 19 % of the total follow-up sample, remitting cases. 13.1 %, new cases, 4.8 % and non-cases. 63.1 %. Continuing cases had a significantly higher utilization of ambulant care during follow-up. They also had 3 times more days of sick-leave. Poor perceived health at index contact, measured using the Nottingham Health Profile (NHP), predicted that the patient became a continuing case during follow-up. Continuing cases, to a greater extent, showed psychosocial stress concerning unemployment, private economy and loneliness/social isolation. Continuing cases also showed a lower satisfaction with primary health care services in all areas measured.