The social work task changes constantly, due to developments in knowledge, and to ideological shifts in the general policy environment. In Northern Ireland, social workers have worked in an integrated health and social service structure since the early 1970s, and though there have been many changes in health policy, very few have had an immediate impact on the delivery of social services. This chapter identifies and discusses developments in health policy in terms of their impact on services for people with mental illnesses in order to highlight areas of concern to users of mental health services and to social workers involved in their care. Community services for people with mental illnesses are particularly difficult to quantify. Mental health legislation was necessary to ensure that individuals were not unnecessarily treated, particularly being confined to a mental hospital with the consequent loss of civil rights. Policy changes affecting the law or service delivery have a direct impact on social work practice.