Do longer job hours matter for maternal mental health? A longitudinal analysis of single versus partnered mothers

Over the past decade, single mothers have experienced increasing work requirements both in the UK and in other developed countries. Our aim was to examine if increasing job hours are associated with mental health of single mothers compared to partnered mothers. Using 13 waves of the Understanding Society Survey (2009–2023), we estimated the relationship between changing job hours and mental health using difference‐in‐difference event study design, accounting for differential treatment effects across time and individuals. We also investigated the role of potential mechanisms, including role strain and additional income. Our findings suggest that increasing job hours from part‐time to full‐time is associated with an instantaneous decrease in mental health of 0.19 standard deviations for single mothers [95% CI: −0.37;−0.01], with no effect for partnered mothers. Further analyses suggest increased role strain for single mothers as a mechanism helping explain these differences. The negative effects of increasing job hours and increased role strain should be considered when developing future welfare policies for single mothers, to ensure that greater work requirements do not undermine the mental health of the already vulnerable population group.