Epidemiologic assessment of overmet need in mental health care.

The traditional purpose of psychiatric epidemiologic surveys has been the assessment of mental illness and, by implication, the need for care. Previous research has focused on unmet need, defined as those who meet "caseness" but do not receive care, but has rarely examined the converse. Since survey respondents receiving care but not meeting caseness have been found to represent up to one-half of mental health service users, this is a significant service delivery issue. The data are drawn from the Mental Health Supplement to the Ontario Health Survey (the Supplement), a household survey of 9,953 respondents, which used the University of Michigan's version of the Composite International Diagnostic Interview (UM-CIDI) as its diagnostic instrument. Community residents who used formal mental health services in the past year but who did not have a concurrent UM-CIDI/DSM-III-R (Diagnostic and Statistical Manual 3, revised) diagnosis were defined as "treated without CIDI disorder". Their need for care was evaluated by comparing them to "treated depressed" and "healthy" respondents, using indicators of functional impairment, vulnerability to developing disorder, and risk of relapse. The match between need and care levels was examined by comparing their type and intensity of use with those of the treated depressed. Results present strong evidence for conceptualizing need as continuous, rather than discrete. The results for the group defined as "treated without CIDI disorder" were consistently between those for the other two groups (with the "treated depressed" always showing the highest need) on all indicators as well as on a summary need index. However, their type and intensity of service use appeared to be unrelated to their level of need. Although some of the "treated without CIDI disorder" group may require preventive or follow-up treatment, the need for service for others is not as convincingly demonstrated. Outcome studies are needed to provide comparative data to describe more fully the problems experienced by this group and indicate whether treatment is helpful. In an age of fiscal restraint, when resource reallocation (rather than generation of new resources) is the likely scenario, such close examination of the fit between need and care is critical if services are to be targeted appropriately.