Objectives: The primary aim of this study was to investigate neuropsychological function in patients with earthquake-related posttraumatic stress disorder, compared with earthquake-exposed but resilient controls. We hypothesised that individuals with posttraumatic stress disorder would have poorer neuropsychological performance on tests of verbal and visuospatial learning and memory compared with the earthquake-exposed control group. The availability of groups of healthy patients from previous studies who had been tested on similar neuropsychological tasks prior to the earthquakes allowed a further non-exposed comparison.
Method: In all, 28 individuals with posttraumatic stress disorder and 89 earthquake-exposed controls completed tests of verbal and visuospatial learning and memory and psychomotor speed. Further comparisons were made with non-exposed controls who had been tested before the earthquakes.
Results: No significant difference in performance on tests of verbal or visuospatial memory was found between the earthquake-exposed groups (with and without posttraumatic stress disorder), but the posttraumatic stress disorder group was significantly slowed on tests of psychomotor speed. Supplementary comparison with historical, non-exposed control groups showed that both earthquake-exposed groups had poorer performance on a test of visuospatial learning.
Conclusion: The key finding from this study is that there were no differences in verbal or visuospatial learning and memory in individuals with posttraumatic stress disorder compared with similarly earthquake-exposed controls. Compared with non-exposed controls, both earthquake-exposed groups had poorer performance on a test of visuospatial (but not verbal) learning and memory. This offers preliminary evidence suggesting that it is earthquake (trauma) exposure itself, rather than the presence of posttraumatic stress disorder that affects aspects of neuropsychological functioning. If replicated, this may have important implications for how information is communicated in a post-disaster context.
Keywords: earthquake; neuropsychological function; posttraumatic stress disorder; trauma-exposed controls.