COVID-19, economic downturn, and long-term trajectories of population mental health: evidence from two nationally representative British birth cohorts at the intersection of gender and socioeconomic position

Background. We examined long-term trajectories of mental (ill-)health in two British generations ('Baby boomers' and 'Generation X') across the life course, including the COVID-19 lockdowns and the subsequent cost-of-living increases. We analysed inequalities by generation, gender, socioeconomic position (SEP), and their intersections, and explored the relationship between inflation and mental (ill-)health post-lockdown. Methods and Findings. We used data from the National Child Development Study (NCDS/1958, n=8,215) and the 1970 British Cohort Study (BCS/1970, n=7,789), with repeated measures of psychological distress (Malaise Inventory) between ages 23-64.5 (NCDS/58) and 26-52.5 (BCS/70). We used multilevel growth curve models to study long-term trajectories, and negative binomial regression models to analyse associations with inflation/cost-of-living in the 2021-2023 period. Distress increased during the pandemic but declined post-lockdown (B _{spline2_quadratic_NCDS/58} =-0.12 [-0.17, -0.08], p<0.001; B _{spline2_quadratic_BCS/70} =-0.16 [-0.21, -0.11], p<0.001). Women and those from disadvantaged childhood SEPs started their trajectories at significantly (p<0.001) higher levels in both NCDS/58 (B _women =0.72 [0.62, 0.82]; B _manual =0.24 [0.14, 0.35]; B _rented7&11 =0.34 [0.22, 0.46]) and BCS/70 (B _women =0.73 [0.62, 0.83]; B _manual =0.23 [0.12, 0.35]; B _rented5&10 =0.30 [0.15, 0.45]), with even larger inequalities for women from disadvantaged childhood SEPs born in 1958 (intersectional effects). None of these inequalities significantly reduced in the long term. Inflation/cost-of-living was significantly associated with distress, but effects did not vary by gender, concurrent SEP, or their intersection. Conclusions. Despite post-pandemic improvements, persistent inequalities by gender and childhood SEP remain. Considering the existing high levels of socioeconomic adversity in the UK, efforts must be made to reverse these gaps and prevent further inequalities later in life and intergenerational transmission.