Cannabis use as a risk factor for psychotic-like experiences: A systematic review of non-clinical populations evaluated with the Community Assessment of Psychic Experiences

Aim: Epidemiological data have provided evidence that psychotic-like experiences (PLEs) can occur in the general population, not necessarily accompanied by the impairment and suffering observed in formal psychiatric diagnoses. According to the psychosis continuum hypothesis, PLEs would be subject to the same risk factors as frank psychosis. The aim of this review was to summarize observational studies that evaluated cannabis use as a risk factor for PLEs as determined by the Community Assessment of Psychic Experiences in non-clinical samples. The instrument composed of 3 dimensions-positive, negative and depressive-is a scale specifically designed to assess the occurrence, frequency and impact of PLEs in non-clinical population. Methods: We searched PubMed/Medline, Web of Science and PsycInfo electronic databases for indexed peer-reviewed studies published until September 2017. Results: We initially identified 100 articles. The PRISMA model for systematic reviews was used and 19 full-text articles were analysed. In general, the findings suggested that the higher the cannabis use and the younger the participants, the higher the reports of PLEs, although associations were more consistent for the positive dimension. Conclusions: More attention should be paid to the understanding of the risk factors of PLEs in the general population, since these experiences are themselves a risk for psychotic disorders.