Pathways to post-traumatic growth and post-traumatic stress following the Canterbury earthquakes in a cohort of 40-year-olds

Objective: To report on post-traumatic growth and post-traumatic stress following the Canterbury earthquakes and to quantify the relationships between exposure to the earthquakes, post-traumatic growth and post-traumatic stress. Method: The Christchurch Health and Development Study is a longitudinal birth cohort study of New Zealanders aged 40 years at the time of latest assessment in 2017. A total of 455 participants were exposed to the Canterbury earthquakes and assessed in 2012 and 2017. Post-traumatic growth was measured in 2017 using the Post-traumatic Growth Inventory. Earthquake-related post-traumatic stress was measured in 2012 using post-traumatic stress disorder items from the Diagnostic Interview Schedule. Post-traumatic growth and post-traumatic stress were modelled using measures of earthquake impact and subjective measures of earthquake consequences (peri-traumatic stress and disruption distress). Results: There was an indirect relationship between earthquake impact and post-traumatic growth. This was mediated via disruption distress. There was also an indirect relationship between earthquake impact and post-traumatic stress. This was mediated via peri-traumatic stress and disruption distress. Post-traumatic growth and post-traumatic stress were not significantly related. Conclusions: Measurement of post-traumatic growth and post-traumatic stress is required for a holistic understanding of disaster consequences. Subjective assessment of distress following disasters is required to predict their psychological effects.