Background: Social networks are important for people with severe mental illness, and services need to assess whether they succeed in improving social contacts.
Methods: In a prospective controlled study, social network data were obtained in an epidemiologically representative sample of people with psychotic disorders both before (Time 1) and two years after (Time 2) the introduction of two sectorised community mental health services in south London (one intensive service with two specialist teams, one standard service with a generic team).
Results: There were significant baseline differences between sectors with social networks being smaller in the sector later served by the intensive service. Social network size increased within the intensive service sector, but not in the standard service sector. There was a significant sector effect for the network component of relatives (intensive > standard) and in the other ('non friends') component (standard > intensive) after adjusting for baseline differences.
Conclusions: The findings suggest that the intensive sector community mental health service enhanced people's social networks with their relatives, relative to the standard service. The reverse is the case for other contacts.