Introduction : The use of illicit drugs by students and the possible psychological repercussions in this population of young adults is an important public health issue. While some data in the literature suggest a relationship between cannabis and the occurrence of mental health disorders, and in particular psychotic illnesses, epidemiologic surveys have shown that cannabis is the most consumed illicit drug in France. Aim of the study : To carry out a quantitative and qualitative epidemiological investigation of substance use within a student population seen during their mandatory preventive health visit at the University medical facility. Method : Students were asked to take part in an investigation of their substance consumption and their individual experiences with cannabis in particular. Personality autoquestionnaires were performed and the psychotomimetic effects of cannabis were investigated with substance use within a student population seen during their mandatory preventive health visit at the University medical facility. Results : A total of 3 807 students took part in the survey with a response rate of approximately 50 %. Preliminary results relating to a subsample of this study are presented here (n = 880, mean age 20 years, 65 % women). 44 % of the students consumed cannabis at least once in their life. The prevalence of regular consumption in students (at least once a week) was of 18 %, 11 % had periods of daily or close to daily consumptions, and 13 % used cannabis in the last month. For each of the drugs cocaine, ecstasy (MDMA), and mushrooms (psilocybin) the prevalence of experimentation (at least once) was 5 % for cocaine, 4 % for ecstasy and mushrooms, and for LSD the rate was 1,5 %. Other evaluated substances had a prevalence of consumption tower than 1 %. For the first cannabis consumptions, a majority of students state to felt pleasant, effects : relaxation (71 %) and euphoria (53 %). 13 % state to have felt effects of anxiety or sadness. 25 % admit having had difficulties of expression, 24 % memory deficits, 35 % trouble with coordination or balance and 39 % difficulties of concentration. Approximately 16 % had impressions of depersonalization and derealization. Lastly, some experienced "psychotic-like" effects such as visual (10 %) and auditory (6 %) hallucinations, as well as referential ideas (16 %), mistrust or feelings of persecution (11 %). 26 % of the student sample had felt at least one of these last four "psychotic-like" effects. Discussion : The results are consistent with the idea that the impact of cannabis consumption is highly variable among different consumers. Implications for prevention strategies are discussed such as educational interventions based on recognition and motivation for change.
