Objectives This study aimed to assess the degree to which the ‘social cure’ model of psychosocial health captures the understandings and experiences of healthcare staff and patients in a social prescribing (SP) pathway and the degree to which these psychosocial processes predict the effect of the pathway on healthcare usage.

Design Mixed-methods: Study 1: semistructured interviews; study 2: longitudinal survey.

Setting An English SP pathway delivered between 2017 and 2019.

Participants Study 1: general practitioners (GPs) (n=7), healthcare providers (n=9) and service users (n=19). Study 2: 630 patients engaging with SP pathway at a 4-month follow-up after initial referral assessment.

Intervention Chronically ill patients experiencing loneliness referred onto SP pathway and meeting with a health coach and/or link worker, with possible further referral to existing or newly created relevant third-sector groups.

Main outcome measure Study 1: health providers and users’ qualitative perspectives on the experience of the pathway and social determinants of health. Study 2: patients’ primary care usage.

Results Healthcare providers recognised the importance of social factors in determining patient well-being, and reason for presentation at primary care. They viewed SP as a potentially effective solution to such problems. Patients valued the different social relationships they created through the SP pathway, including those with link workers, groups and community. Group memberships quantitatively predicted primary care usage, and this was mediated by increases in community belonging and reduced loneliness.

Conclusions Methodological triangulation offers robust conclusions that ‘social cure’ processes explain the efficacy of SP, which can reduce primary care usage through increasing social connectedness (group membership and community belonging) and reducing loneliness. Recommendations for integrating social cure processes into SP initiatives are discussed.