Introduction

In a typical study evaluating the changes produced in a community by the introduction of community psychiatric services, an assessment of the utilisation of psychiatric care is made before the introduction of these new services and utilisation is then assessed after the services have been in place for some period of time. The impact of the community mental health centres (CMHCs) is measured by the pre-post changes observed and may be attributed to the effects of the introduction of the new services (Wing & Hailey, 1972; Hafner & Klug, 1982; Stefansson & Cullberg, 1986; Rudas, 1990; Tansella et al., 1991; Sogaard, 1993). Few studies of service-level outcome have employed a control district (Haroutun & Babigian, 1977; Valbak et al., 1992). Only, however, if changes observed in the intervention districts are not noted in the control districts can we be justified in attributing the changes in utilisation of services to the introduction of the new services.

Most research evaluating the effects of the institution of community psychiatric services describes changes in inpatient, outpatient and CMHC utilisation. The introduction of a CMHC may, however, affect other parts and functions of the community such as the social welfare system, privately practising psychiatrists and general practitioners. Indeed this is often an aim of these centres. Thus, potentially important effects of the new CMHC may be overlooked if the assessment of the effects is not comprehensive.

This chapter presents data which speak to the issue of control districts and comprehensiveness of design by describing an evaluation project conducted in Copenhagen: The Copenhagen Community Psychiatric Project (CCPP). The remainder of this chapter will include a description of the Danish mental health care system and the background of the evaluation project, details of the methodology of the project, results of the changes in utilisation which followed the introduction of the CMHC and data relating to our attempt to increase the comprehensiveness of an assessment of change. In appropriate analyses the importance of control groups will be highlighted.

Background

The Danish social welfare system ensures basic economic support for all residents of Denmark. Health services (including psychiatric services) are a part of a national health system.