Mental health after compounding natural hazard exposure in New South Wales from 2019 to 2023: a cross-sectional study in Australian youth.

Direct exposure to fires and floods adversely impacts mental health, although less is known about youth wellbeing after compounding natural hazards in short time frames. A youth sample aged 16-25 years completed self-report measures of adjustment disorder, alcohol/substance misuse and dependence, depression, anxiety and stress symptoms, and climate change anxiety after drought, bushfire and flood events in New South Wales. From 877 respondents, direct exposure to compounding (i.e., ≥ 2) natural hazards occurred in 182 persons and single hazard in 267. Compounding hazards increased odds for alcohol/substance misuse and dependence (adjusted odds ratio [OR] 2.19, 95% confidence interval [CI] 1.39-3.45) and anxiety (adjusted OR 1.55, 95% CI 1.04-2.30) by comparison to single hazard exposure. There was no interaction between compound hazard and life stressors (quantified by the Adjustment Disorder New Module-8). The association between compounding hazard exposure with mental health was mediated by climate change anxiety; full mediation for adjustment disorder, depression, anxiety, and stress, and partial mediation for alcohol/substance misuse and dependence. Compounding natural hazard exposure may have specific rather than global mental health impacts and is mediated by climate change anxiety. Youth may require specific support to recover from compounding hazards to promote wellbeing and manage climate change anxiety.