Socially marginalised people with mental health disorders have complex needs that require integrated care. However, mental health and social care sectors are fragmented, and inter-organisational collaboration is challenging.

A cross-national whole Network Analysis was carried out to detect and interpret patterns of relations between mental health and social care services in several European cities and assess their levels of care integration, following Leutz's levels: linkage, coordination and full integration.

Data on referrals and service routine meetings were collected in deprived areas of 14 European cities and processed within a Social Network Analysis approach. Structural indicators included degrees, components and overlapping cliques, betweenness centrality and centralisation and brokerage roles. Patterns of collaboration were compared across cities.

Few cities had full integrated services. Whole networks had relatively low densities, including denser sub-networks of similar services. The linkage across sectors remained weaker than the linkage within sectors. Services situated in broker positions were not always integrated nor commissioned for care coordination. The centrality of these services was higher when the linkage density was lower.

Although differences between structural patterns of mental health and social care networks mainly depend on national care integration policies, the study revealed structural gaps in the achievement of these patterns, whatever the policy model. This could explain why different systems are basically facing the same problems in service delivery despite these differences. These gaps constitute potential weaknesses in the quality of mental health and social care integration at the system level.