The project described in this chapter was designed to establish rates of severe mental illness (SMI) in both health and social services, and explore the extent to which both served similar or different populations. The research was funded as part of the Department of Health central policy research initiative. It began on January 1st 1997 when the mental health policy agenda was at an early stage in its present course. The data from the present study represent a unique baseline assessment of the nature of provision by community-based staff in the period immediately before the introduction of the National Service Framework (NSF) (DoH, 1999) and related policy. The main areas to be covered in this chapter include:

developing a definition of SMI, which will concentrate on the 'M3' score. This is a method that conceives of SMI as a continuous rather than a categorical scale ('SMI' or 'not SMI'), which marks it out as different from other attempts at definition and allows the threshold for SMI to be varied. It also does not require a client to have a diagnosis of a psychotic illness;

the relationship between SMI and the care programme approach (CPA) (The CPA ensures that everyone who comes to mental health services for help: has their needs assessed; is provided with a key worker; receives a care plan; and, has their needs reviewed when needed. Trusts have flexibility in deciding on what levels of CPA they chose to adopt);

comparing health and social services;

investigating met and unmet needs of clients with SMI characteristics; and,

other relevant findings.