Does neighbourhood-level social capital affect mental health?

Background

Social capital - the trust within communities, shared resources, values, and connections - has been linked to mental health. Strong ties within a community may protect against mental health problems, but it is not clear if low social capital is a risk factor for psychotic and bipolar disorders.

Why did we do this research?

There is very little longitudinal evidence looking the link between social capital and risk of developing psychiatric disorders.

What did we do?

Study population: We used data Stockholm County in Sweden. We included 1.47 million adults born in Sweden who were living in Stockholm county after 2002.

Exposure - social capital: We measured median levels of neighbourhood trust across all neighbourhoods (SAMS) in Stockholm County, based on responses to 13 questions in the Stockholm Public Health Cohort Survey. Broadly, these questions measured levels of political trust, welfare trust, and personal trust.

Outcome - major psychiatric disorders We used linked health care records to look at diagnosis of major psychiatric disorders, including:

• Non-affective psychosis (including schizophrenia)

• Affective psychotic disorders (e.g. bipolar disorder with psychosis)

• Bipolar disorder without psychosis

Analysis: We first explored correlations between psychiatric disorders and neighbourhood-level social capital. We then used multilevel survival modelling to explore if exposure to social capital was associated with the three psychiatric outcomes, which we also adjusted for a range of factors.

To check that the results were robust, we did several sensitivity analyses. First, we re-calculated neighbourhood social capital scores excluding those who went on to develop psychiatric disorders. We also did an instrumental variable analysis using median neighbourhood votor turnout as an instrument for personal in the neighbourhood.

What did we find?

Social capital affected the rates of major psychiatric disorders.

Importantly, this association depended on your migrant background. High levels of social capital was associated with lower rates of psychiatric disorders in the Swedish-born group and for others of European heritage. However, for people of Sub-Saharan African, North African, or Middle Eastern heritage, high levels of social capital was associated with higher rates of psychiatric disorders.

What does this mean?

This different finding for Swedish-born and migrant groups suggests that there is a protective effect of social capital for the Swedish group, but that social capital may act to exclude minoritised groups, consequently increasing rates of mental illness in these groups.

If causal, these results suggest that social capital can be beneficial in the general population, however it is important to consider the impact on minoritised groups as it may be harmful for different groups in the population.

Read more

You can read the full paper here Nature Mental Health.

Read a summary of this work on the Karolinska Institutet site

Open science

Pre-registered protocol: OSF Pre-print: PsyArXiv Analytic code: OSF

Behind the research

This project started as an Angela Song-Chase’s MSc project, supervised by Prof James Kirkbride and me. James conducted additional sensitivity analysis to strengthen the manuscript, providing an exemplar of a rigorous exploration of this research question.