[Prevalence and follow-up of psychiatric diseases in internal medicine departments].

While several surveys have shown that psychiatric disorders are common in non-psychiatric hospital departments, information on the course of psychiatric morbidity during the hospital stay is still lacking. Therefore, in two medical hospital departments in Austria we investigated the course of illness in 265 patients staying in the hospital for more than four weeks. Patients were interviewed using the Clinical Interview Schedule. At admission, prevalence of all psychiatric disorders was 46.0%. During the four weeks after admission, mentally well were discharged from hospital more frequently than mentally ill. Among those staying in the hospital after four weeks, prevalence was 51.4%. In the intervening period, the incidence (9.5%) was slightly lower than the rate of remission (12.4%). At both assessments, organic mental illness was the most frequent diagnosis followed by neurotic and adjustment disorders. Thus, in spite of the slightly higher rate of remission than incidence, the overall psychiatric prevalence increased during the first four weeks after admission because of the earlier discharges of the mentally well. In conclusion, our results show that point-prevalence surveys not regarding disease course give an incomplete impression of psychiatric morbidity in non-psychiatric hospital departments.