Narcotics controls measures are being intensified specially at ski resorts during winter. Over the past decade, the French Alps experienced several cases of fatal accidents at high altitude. This study aims to determine the prevalence of psychoactive substances used in fatal high altitude accidents.

A 10-year retrospective study was conducted including data from 2014 to 2023. These accidents occurred in the French Alps, within the departments of Haute-Savoie, Savoie, Isère, Hautes-Alpes and a part of Drôme. Only fatal accidents that occurred during high-altitude activities (above 1000 meters), and for which no medical cause of death was identified were included.

Among the selected cases, 99 victims were male and 22 were female, with a median age of 42 years. The most common types of accidents involved skiing/snowboarding, followed by flying in all types of aircraft, sport climbing and outdoor excursions, water sports such as canyoning and kayaking, and other types of high-altitude activities. One hundred and twelve cases were negative, while nine were positive for cannabis consumption, with six individuals being under the influence at the time of death.

In this study, cannabis was the only narcotic detected in fatal high-altitude accidents, demonstrating a prevalence of 5%. This finding suggests that cannabis consumption constitutes an additional risk factor. Targeted prevention programs could be considered to reduce cannabis use during mountain activities.