Abstract
Background: The Canterbury earthquakes started with a 7.1 magnitude earthquake on 4 September 2010 and continued for an extended period with further major earthquakes and over 10,000 aftershocks. Methodological limitations are common in studies measuring the psychological impacts of disasters and affect the quality of findings in this area. In addition, between disaster heterogeneity means local research is required to understand the psychological impacts of the Canterbury earthquakes.
Methods: A systematic review was undertaken examining the literature relating to disasters, and psychological distress and psychiatric disorder. A further systematic review summarised local studies reporting the psychological impacts of the Canterbury earthquakes. A series of studies paying heed to quality methodological indicators was completed reporting the psychological impacts of the Canterbury earthquakes.
Results: The Canterbury earthquakes were associated with small, widespread, and persistent adverse effects. The accurate assessment of psychological impacts relating to disasters is aided by careful sample selection, longitudinal data, and appropriate controls. Measures of post-traumatic growth are required for growth following adversity to be quantified. Post-traumatic growth and post-traumatic stress were predicted by subjective measures of distress relating to the earthquakes as opposed to the severity of shaking.
Conclusion
Methodological factors are important in determining the extent of psychological impacts of the Canterbury earthquakes. Key considerations include the degree of earthquake exposure, choice of outcome measurement, timing of assessment, and appropriate comparators. The extent of adverse psychological impacts following the earthquakes is less after long-term factors causing an increase in psychological morbidity are taken into account. Within the wider population affected by the earthquakes, there are likely to be groups with greater adverse effects. The majority of negative impacts are experienced over the short-medium-term although increased anxiety disorder symptoms were still detected seven years after the onset of the earthquake sequence.