It is already known that a traumatism, whatever nature or gravity, could lead to acute stress symptoms and a posttraumatic stress disorder (PTSD) one month after (1). In the last decades, less than ten studies showed that avalanche survivors are likely to develop PTSD, even sixteen years after exposure (2, 3). In those studies, authors focused on natural disaster avalanches (on habitations or roads). This study would like to evaluate psychological impact of an avalanche accident occurring during mountain recreational activities.

The primary outcome concerns the research of PTSD symptoms using the Impact of Event Scale - Revised (IES-R). It is a 22 items scale, which explores specifics symptoms of Post Traumatic Stress Disorder that may have occurred during the week before the interview. It concerns 3 different possible areas of PTSD: intrusion (eight items), avoidance (eight items) and hyperarousal symptoms (six items). Each item ranges from 0 (not at all) to 4 (extremely). The total score of the IES-R ranges between 0 and 88. A score equal or more than 33 is highly in favour of PTSD (91% sensitivity, 82% specificity, 90% positive predictive value and 84% negative predictive value). However, above 33 the diagnostic of posttraumatic stress disorder must be confirmed by a psychiatric analysis. Our results will be separated in two categories for the analysis: 1) IES-R score higher or equal to 33; 2) IES-R score lower than 33.

The secondary outcome is the result of the Short Form 12 questionnaire (SF-12). The SF-12 consists of 12 items selected from the "Medical Outcomes Study 36-items Short-Form Health Survey" (SF-36) to reproduce the Physical Component Summary and Mental Component Summary scales in the general US population. The SF-12 Health Survey was developed in the United States to provide a shorter alternative to the SF-36. The SF-12 contains a subset of 12 items from the SF-36, including one or two items from each of the eight SF-36 scales (general health, physical role, physical bodily, vitality, social and emotional functioning, role emotional and mental health). SF-12 Physical and Mental Components are scored from 0 to 100. A higher score indicates a better health state. Scores will be compared to literature data.

Study population concerns avalanche survivors in the French Northern Alps during the last four years. Furthermore, the investigators will try to identify risk factors to develop PTSD in these circumstances. They will try to know if survivors have changed their mountain practice after the accident. From 2014 to 2018, there were 211 avalanche victims in the French North Alps included in the North Alpine Avalanche Register (RENAAV), 132 victims survived. Considering the rate of non-response, the investigators are expecting between 50 to 80 subjects to be analysed. Data will be collected in the medical records and during a phone interview with a standardized questionnaire. A rate of 9,2 % of posttraumatic stress symptoms is expected, corresponding to the prevalence of PTSD (1) after traumatism.

Concerning statistical analysis, quantitative data will be described in terms of mean, standard deviation, median and extreme values. Qualitative data will be described in terms of absolute frequency and percentage by modality. The 95% confidence intervals will be presented. Quantitative data will be compared by a Student's parametric test, replaced by the Wilcoxon test in case of deviation from the normality of distribution. Categorical data will be compared by a Chi 2 test or Fischer's exact test in case of too small sample. A threshold of significance will be retained for a value of p \< 0.05. Univariate and multivariate analyses will be performed to independently identify risk factors at a higher frequency of PTSD.

The research team received the approval of ethical research committees since the March 19th of 2019.