Prevalence and intensity of basic symptoms among cannabis users: an observational study

BACKGROUND: It is difficult to establish whether people who are prone to psychosis are drawn to cannabis use or whether cannabis use truly increases the incidence of psychotic experiences. OBJECTIVES: The aim of our study was to evaluate, in a sample of healthy high school and university students, the presence and level of subjective experiences (SEs) and their relation to cannabis use. METHODS: A total of 502 voluntary subjects were recruited; an anamnestic interview was administered to obtain socio-demographic information, cannabis use data, and psychiatric familial history. SEs were assessed using the Italian version of the Frankfurt Complaint Questionnaire (FCQ). RESULTS: One hundred and fourteen subjects declared the use of cannabis: 20.5% smoked more than 1 joint per week, and 71.9% used cannabis for a period of more than 1 year. Cannabis users did not differ from the cannabis-free group in any of the 10 FCQ dimensions. Higher FCQ total scores were found in cannabis users with a familial history of psychiatric disorders respective to those without a psychiatric load (p<.05). CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: In our study, SE intensity was not influenced by the use of cannabis. With regard to familial data, this is the first study to explore the relationship between SE and the presence of psychiatric problems in first-degree relatives. The association between FCQ intensity and psychiatric familial load may confirm the independence of these phenomena from the use of cannabis.