Patterns of cannabis use, psychotic-like experiences and personality styles in young cannabis users.

Objective: To examine the influence of personality traits on the relationship between cannabis use and psychotic like experiences (PLEs) in young adults.

Method: 499 lifetime cannabis users aged 18 to 25years completed an online survey assessing PLEs using the positive scale of the Community Assessment of Psychic Experiences (CAPE) and personality styles using the Brief Schizotypal Personality Questionnaire (SPQ-B) and the Substance Use Risk Profile Scale (SURPS), a measure of trait hopelessness, anxiety-sensitivity, impulsivity and sensation seeking. Cannabis use was assessed using items from the Youth Risk Behaviour Survey (YRBS) and a self-report measure of the lifetime level of cumulative cannabis use.

Results: Cannabis use as well as schizotypy and the four SURPS personality risk profiles were significantly associated with the frequency of PLEs in young cannabis users. The cumulative levels of lifetime cannabis exposure, trait schizotypy and hopelessness were the strongest predictors of PLEs in the multivariate analysis. Little evidence of a moderating effect of the personality risk profiles on the relationship between cannabis use and PLEs was found. Trait hopelessness was found to have a moderating effect on the relationship between the recency of cannabis use and the frequency of PLEs.

Conclusions: The cumulative levels of lifetime cannabis exposure, trait schizotypy and hopelessness were associated with PLEs in young cannabis users. Individuals with high levels of trait hopelessness who use cannabis may be at higher risk of PLEs. Future research is required to increase understanding of the relationship between cannabis use and PLEs, using more complex moderation models containing personality traits along with other risk factors for PLEs.