Mental health inequalities represent one of the most pressing and persistent challenges in public health, yet the mechanisms through which environmental conditions and socioeconomic disadvantage jointly drive them remain poorly understood, particularly at the fine geographical scales needed to guide intervention. Analysing population-level data from 3.4 million residents across two geographically and socioeconomically diverse English regions, we present the first spatial epidemiological study to simultaneously examine the independent and combined effects of transportation-related air and noise pollution on depression prevalence across all domains of neighbourhood-level socioeconomic deprivation. Applying Generalised Structural Equation Spatial Modelling at Lower Super Output Area level, we first identify place-specific mediation pathways that are invisible to conventional, non-spatial approaches: in rural areas, 24-hour noise exposure mediated 18.64% of the relationship between neighbourhood crime and depression, whilst in urban settings, combined environmental stressors accounted for 41.37% of the effect of income deprivation on older adults' mental health — with suppression effects revealing complex, context-dependent mechanisms that challenge simplistic linear models of environment and mental health. Depression determinants operate through interconnected, place-specific pathways rather than isolated factors, with mediation directionality varying markedly by region and urban-rural context. By conceptualising depression as emerging from dynamic human-environment interactions shaped by local geography and social disadvantage, our work advances the ecological framework of mental health and provides a critical evidence base for targeted, place-sensitive public health interventions addressing the environmental determinants of psychological wellbeing across diverse geographical contexts. • Novel understanding of depression's ecology through innovative spatial analysis of psychological responses to environmental conditions. • First study revealing how built environment stressors and socioeconomic factors jointly shape mental health pathways through psychological mechanisms. • Transportation pollution in built settings may compound deprivation impacts on psychological wellbeing in vulnerable populations. • Environmental-psychological interactions operate through context-specific geographic mechanisms across urban and rural settings. • Place-sensitive approaches are needed to address mental health inequalities by understanding human-environment relations across diverse contexts.
Tsimpida et al. (Sun,) studied this question.