Deinstitutionalization of psychiatry in Denmark has been extensive and the number of psychiatric beds per 1,000 inhabitants is among; the lowest in Europe. The effect of supplementing hospital treatment with treatment in community mental health centres was evaluated in a quasi-experimental design. The patient group examined consisted of patients with long-term contact with psychiatric services. When development in intervention and control districts was compared, the only significant difference was that the total patient group in the intervention district had an increased number of day attendances per year. Comparison of patients from intervention districts who attended day-centres regularly with patients from control districts before and after implementation of community mental health centres indicated that patients from intervention districts had a reduction in the use of inpatient services, a significant increase in quality of life and a significant decrease in the presence of the negative symptom, alogia. We concluded that implementation of community mental health centres can increase the quality of life for the patients and decrease the frequency of the negative symptom, alogia.