The trajectory of symptom burden in exposed and unexposed survivors of a major avalanche disaster: a 30 year long-term follow-up study.

Background: Limited research exists concerning the long-term effects of avalanches on survivors' mental health beyond the first years after the accident. The aims of this study were to describe and evaluate possible differences in long-term mental health symptoms after a major avalanche disaster between exposed and unexposed soldiers using a longitudinal design.

Method: Present mental health symptoms were examined among avalanche exposed (n = 12) and unexposed (n = 9) soldiers by PTSS-10, IES-15 and STAI-12 in four waves (1986-1987 and 2016).

Results: Binary logistic regression revealed that the odds to score above the cut-off were significantly lower for both groups after one year compared to baseline for PTSS-10 (p = 0.018) and significantly lower after 30 days compared to baseline for IES-15 (p = 0.005). Data did not reveal significant differences between the exposed and unexposed groups regarding adjusted PTSS-10, IES-15 or STAI-12 mean scores compared. Linear mixed model-analyses revealed significant effects of time. The adjusted mean scores declined over time for both groups: PTSS-10 (p = 0.001), IES-15 (p = 0.026) and STAI-12 (p = 0.001), and the time trajectories for PTSS-10 were significantly different between the groups (p = 0.013). Although not significant (all p > 0.05), results indicated that a larger proportion of soldiers in the exposed group experienced posttraumatic stress symptoms (5/12) (PTSS-10 score ≥ 4) and distress symptoms (6/12) (IES-15 score ≥ 26) above cut-off points, 30 years post-disaster.

Conclusions: The course of mental health symptoms may persist, and even increase, in selected and trained military personnel 30 years after exposure to a natural disaster. These findings may be of great importance for health authorities planning appropriate follow-up.