Support for populist candidates predicted by declining social capital and an increase in suicides

The recent increase in support for populist candidates in elections across the world has received considerable attention and is of broad scientific and public interest. Two of the most common explanations for this surge are that populism is a consequence of fundamental changes in the workforce stemming from globalization and that it is a cultural backlash to rapid changes in societal values. Here, we test what we call ‘the social isolation hypothesis,’ which hypothesizes that the rise in support for populism is produced by a decline of social capital which increases loneliness and undermines mental health. Using longitudinal census, mortality, and election data, we find that changes in variables related to social isolation—deaths from suicide or alcohol, and an overall decline in social capital—predict support for populist candidates. This supports the idea that the deterioration of the strength of social relationships can affect voting behavior.