Differential Impact According to Mission’s Operational Intensity on Psychoactive Substance Use: A Retrospective Cohort of French Male Army Service Members

International audienceBackground: Stressful deployments in combat areas are known to increase the risk of substance abuse in military personnel. Objectives: The aim of the study was to compare deployment on stressful, high-intensity missions (HIMs) to deployment on low-intensity missions (LIMs) in order to understand factors associated with substance use variations across the mission. Methods: A retrospective cohort study based on a one-shot self-questionnaire was performed four months after their return on two samples of male French Army service members: one returning from an HIM and one from an LIM. The questionnaire focused on tobacco, alcohol, cannabis, cocaine, and psychoactive medication use at three times: before, during, and after the mission. Results: During an HIM, the frequency of tobacco use increased, alcohol use remained stable – although 38% declared a decrease in consumption – and illicit drug use decreased. During an LIM, tobacco and alcohol use increased, cannabis use remained stable, and only cocaine and medication use decreased. After their return, use levels among both samples reverted to values similar to those reported before the mission, except for a decrease in tobacco use observed at return from an HIM. The main factors perceived as related to variations were stress in an HIM and low cost in an LIM. Conclusions/importance: The study suggests a differential impact of deployment on substance use according to the operational intensity of the mission. Variations in use are predominant during the mission with a washout effect after returning home