Background: Since the 1978 Italian reform, an integrated network of community mental health services has been introduced. With few exceptions, research on determinants of mental health service use at the district level has focused on inpatient activities and social deprivation indicators. The European Psychiatric Care Assessment Team (EPCAT) standardized methodology allows for an evidence-based comparison of mental health systems between geographical areas., Aims: To compare service provision and utilization between local catchment areas; to explore quantitative relationships between residential and community service use and socio-demographic indicators at the ecological level., Methods: The European Socio-demographic Schedule (ESDS) was used to describe area characteristics, and the European Service Mapping Schedule (ESMS) to measure service provision and utilization in 18 catchment areas in Piedmont., Results: Substantial variation in service use emerged. Acute hospital bed occupancy rates were lower in areas with more intensive community continuing care service users and with a smaller percentage of the population living alone. The non-acute hospital bed occupancy rate was directly related to the percentage of the population living alone or in overcrowded conditions, and to the level of mobile continuing care service users. Community continuing care service use was highest in areas with a larger percentage of the population living alone., Discussion: Multiple regression models explained between 48 and 55% of the variation in inpatient and community service use between areas. Relationships based on ecological characteristics do not necessarily apply to the individual. This level of assessment, however, is necessary in evaluating mental health policy and service systems, and in allocating resources., Implications for Health Care Provision and Use: The distribution of mental health care resources should be weighted in terms of indicators of social deprivation shown to be important predictors of both inpatient and community service use, as these are likely to be related., Implications for Health Policies: To ensure horizontal equity in access to mental health care, particularly for people with severe mental illness, evaluation of mental health policy should be based on a concurrent evidence-based assessment of the organization and use of both residential and community services, in relation to area level indicators of social deprivation., Implications for Further Research: Cross-national research using an internationally standardized methodology should consider the influence of the social network independently of other socio-economic indicators, to verify the relative importance of this in predicting service use in southern and in northern European countries.