Is it the place or the people in the places? Exploration of why young people in deprived coastal communities of England have worse mental health than their peers inland

• English adolescents’ mental health is lower in coastal, vs inland, deprived areas. • We used twelve waves of a nationally representative study of adolescents living in England from 2009-2020. • We linked individual and environmental measures to where respondents lived during adolescence. • We then followed them up to 11 years later to assess their mental health as young adults. • Keys drivers of the coastal mental health gap were household socio-economic circumstances. • Investments should be made in deprived coastal areas to tackle the drivers of poor mental health. Previous research has shown that English adolescents who lived in the most deprived coastal neighbourhoods had worse mental health up to 11 years later than if they had lived in equivalent inland neighbourhoods. We used the same twelve waves (2009-2022) of Understanding Society, to examine whether this association was explained by the places the study members lived (31 objectively measured built, social, economic and educational indicators linked via residential lower-super output areas) or their collective individual socio-demographics when they were adolescents (aged 10-15yrs). Coastal youth (n=764) were exposed to worse average levels of sixteen environmental measures and better average levels for five environmental measures, than their peers inland (n=4,157). The concentration of area deprivation was also greater for coastal youth compared with their inland peers. When longitudinal models were fitted between environmental measures and SF-12 mental functioning scores (MCS) during adulthood (age 16+), only local crime and higher education participation were independently associated with MCS [Top 20% vs Bottom 20% (95% Confidence interval): -1.20 (-2.38, -0.03) and Middle 20% vs Worse 20%: 1.07 (0.09, 2.05)] after adjustment for socio-demographics. As well, the amplified effect of area deprivation on MCS in coastal, compared to inland, areas was reduced the most by adjustment for individual socio-demographics [interaction term coastal*Top20% deprived area: -5.1 (-8.1, -2.2) to -4.3 (-7.0, -1.6)], rather than the two environmental measures [further reduced to -3.9 (-6.7,-1.1)]. Results from this paper suggest policies to improve young adult’s mental health in England should target the socioeconomic circumstances of households in the most deprived coastal areas.