This study investigates health and mental health services use by adults with and without newly incident mental disorders and uses prospectively gathered data from the Epidemiologic Catchment Area Program, a multi-site interview survey of adult household residents in the United States. Study subjects were 13,400 participants who completed interviews in the initial survey and also in a follow-up 1 year later, and who reported no contact with mental health services in either the specialized mental health sector or in the general medical sector in the 6 months prior to the initial survey. Case ascertainment was by means of a standardized interview method, the Diagnostic Interview Schedule. Separately, and before the mental health assessments were made, respondents were asked about their use of health and mental health services. 'Hierarchical' and 'filter' models of mental health services provide frameworks useful in understanding the possible effects of specific categories of psychiatric disturbances on use of health services. Only a minority of individuals with newly incident psychiatric disorder report discussion of mental health issues in a health care setting. Persons who developed a mental disorder during the follow-up interval were just as likely to consult a non-psychiatrist physician for their mental health problems as to consult a specialist in mental health, even accounting for other factors known to be associated with differential use of health care services. This large community study of incident psychiatric disorders strengthens prior evidence on the importance of the general medical sector in the care of individuals with psychiatric disturbances.