The long-term impacts of the Canterbury earthquakes on the mental health of the Christchurch Health and Development Study cohort.

This article examines the long-term mental health impacts of the Canterbury earthquakes on participants of the Christchurch Health and Development Study (CHDS), a 40-year longitudinal birth cohort study from New Zealand. Seven years after the earthquakes began in 2010, increased exposure was associated with higher rates of anxiety disorder symptoms and cumulative increases in symptoms of post-traumatic stress disorder (PTSD), anxiety disorder, nicotine dependence, and total psychiatric disorders, although the overall attributable fraction of mental disorders linked to the earthquakes was small (approximately 6% over seven years). After adjusting for confounding factors such as prior mental health history and socio-demographic variables, the magnitude of these associations diminished, suggesting that pre-existing vulnerabilities and social factors also contributed to mental health outcomes. The findings indicate a temporal gradient with stronger adverse effects closer to the disaster and highlight the importance of considering long-term psychological consequences of natural disasters within their broader social context.