Le cannabis dans les armées est une réalité que nous avons choisie d’inscrire ici dans une temporalité ; le passé tout d’abord, depuis le concept d’hygiène mentale à l’histoire du cannabis et de sa diffusion dans la population française comme préalable à une tentative de compréhension de l’intérêt actuel pour le cannabis dans les armées. Son actualité s’est déclinée en celle du contexte épidémiologique de son usage en milieu militaire pour lequel nous avons rappelé les principales études dont le cannabis a pu faire l’objet. Cette actualité fut également celle d’une recherche clinique visant à évaluer en population militaire un outil de repérage des consommations problématiques de cannabis, le questionnaire CAST.

Cannabis in the army is a reality the authors have chosen to inscribe in a temporality, from the concept of mental hygiene to the history of cannabis and of its spreading in the French population, so as to apprehend the present interest in cannabis in the army. Consumption of psychoactive drugs in military forces actually dates back to some decades, no doubt it has given rise to a specific interest of the medical corpse in dealing with these consumers both in their medical treatment and in pure prevention as well as in expertise. The military hierarchy is equally interested in these two last domains, keeping strictly to its role without interfering in the medical field. The extent of this addictive phenomenon in the general population had to include the military domain in spite of the selective recruitment practised. This phenomenon was studied through a drug, cannabis, and via the most salient points: the media coverage of its use in the military institution; the frequency of use of this substance particularly by young adults; the legal repression of its consumption as a product classified as narcotic; its dangerousness in connection with the specificities of military duties. After having characterised the epidemiological context of the use of cannabis in the army, the authors studied its topicality by a clinical research to estimate a screening test of problematic uses of cannabis, the CAST questionnaire, in a military population. Specifically dedicated to cannabis, it was used in recent years in most of the representative enquiries of the level of psychoactive drugs use by the French observation system. Unlike other screening instruments as Fagerström for tobacco or DETA for alcohol, the validity of CAST had not been thoroughly studied until this loophole was recently closed. Our study aimed at expanding the available data concerning a specific population due to a medico-statutory demand. Its methodology consisted in a questionnaire including CAST and a psychiatric interview the result of which was a medical record specifying possible cannabis addiction and indicating determinants of its use. The psychometric qualities of CAST were confirmed both in its internal consistency and its specificity as well as in its sensitivity with a consumption risk threshold of three. The data of prevalence of cannabis consumption was added to results of previous studies of military populations although no correlation could be established with other risk factors (psychopathology, environment). The medico-military dimension of cannabis consumption was objectivised excluding the overreactions which may occur in a highly regulated environment but with the reservations due to the size of the population studied. The CAST questionnaire appears to be accepted as effective screening tool via its qualities of discrimination and feasibility and made easy by its quick and simple use. Its use by unit medical doctors seems adequate to help them approaching cannabis consumers provided that it is part of the healing process that should not be used alone. Such an approach with the use of CAST facilitates the meeting and the weaving of a link with the patient who may be in a conflicting relationship with his environment. Raising awareness of the different interested players and giving them some adequate training are desirable accompanying measures of CAST implementation in medical service units to improve its operational character.