Development and predictors of psychological outcomes following the 2008 earthquake in Iceland: a longitudinal cohort study

Abstract

Aims: On 29 May 2008, an earthquake struck in South Iceland. The aim of this study was to explore the trajectories of post-traumatic stress, depressive and anxiety symptoms among exposed inhabitants during the first year following the earthquake, as well as predictors for symptomology.

Methods: This was a longitudinal cohort study based on a sample that was randomly selected from the earthquake-stricken area ( n = 1301). Participants answered a questionnaire assessing demographic and disaster-related factors 2 months after the earthquake. In addition, symptoms of post-traumatic stress disorder (PTSD), depression and anxiety were assessed 2, 4, 8 and 12 months post-disaster.

Results: Two months after the earthquake, 5.2% of the participants reported PTSD symptoms, 6.7% depression and 6.4% anxiety symptoms. When comparing first and last time points only, we found a significant decrease in anxiety ( p = 0.05), particulary among females ( p = 0.05), those with a primary education ( p = 0.01), prior history of accidents/disasters ( p = 0.02) and those experiencing damage to their home ( p = 0.02). No significant trends were found when the development of other symptoms between the four time points was assessed.

Conclusions: Findings indicate a reduction in anxiety symptoms between 2 and 12 months post-disaster, with PTSD and depression symptoms remaining fairly constant across time. No trends in symptomology were observed over time. The results highlight the need for continued monitoring of those affected by disasters and the identification of subgroups at risk in the aftermath of natural disasters.

Keywords: Epidemiology; anxiety; cohort studies; depression; disasters; earthquakes; longitudinal studies; post-traumatic stress; social support; stress disorders.