Mental health care epidemiology seeks to investigate the practical situation of the health care system and services for individuals with mental disorders. In the past decades, mental health care structures in Germany were successively transformed from long-term inpatient treatment capacities to decentralized outpatient and day clinic services. Currently, the proportional relation between treatment facilities in different settings has been stabilized and the strategy of mental health care development focuses on innovative and integrative models of care provision. The aim is to integrate fragmented services by the introduction of network structures to overcome rigid sector boundaries. The need for health care services is associated with multiple factors such as population-based epidemiological data, usage behavior, and health politics. Due to scarce data and poor standards of care it is difficult to determine if current structures of mental health services cover the actual needs. Therefore, a substantial increase of mental health service research is needed.