Background. People with a mental disorder have high rates of service utilization for emotional or addiction problems. Little is known about the role of functional impairments and low social support in such service use. This article investigates: (1) whether the presence of multiple functional impairments mediates the link between mental disorder and service use; and (2) whether social support modifies that association.

Methods. Data were derived from the Netherlands Mental Health Survey and Incidence Study, NEMESIS, a prospective general population study. Predictors of service use (mental disorder; functional impairments; social support) were recorded in the second wave of the study, and service use in the third wave.

Results. Persons with a DSM-III-R disorder and persons with multiple functional impairments were three to seven times as likely to use primary or mental health care. People with low perceived social support were two to three times as likely to use them, and living alone increased the likelihood by 30% to 80%. The effect of mental disorder on service use was mediated by multiple functional impairments. In people with a mental disorder, low levels of social support intensified mental health service use.

Conclusion. Service utilization by people with mental problems can be better understood through a model incorporating: (1) independent effects of mental disorder, functional impairments and social support on service use; (2) a mediating effect of multiple functional impairments on the link between mental disorder and service use; and (3) interaction effects of mental disorder and low social support on service use.