Cannabis with high cannabidiol content is associated with fewer psychotic experiences

Objective: Cannabis is associated with psychotic outcomes in numerous studies, an effect that is commonly attributed to Delta (9)-tetrahydrocannabinol (Delta 9-THC). An increasing number of authors identify cannabidiol, another component of the cannabis plant, as an antipsychotic agent. The objective of the current study is to investigate the role of cannabidiol content in the association between cannabis use and psychiatric symptoms in a large non-clinical population of cannabis users. Methods: In a web-based cross-sectional study we obtained detailed information about cannabis use and subclinical psychiatric experiences using the Community Assessment of Psychic Experiences (CAPE). Different types of cannabis (i.e. marijuana, hashish etc.) have distinctive proportions of Delta 9-THC and cannabidiol. Since average concentrations of Delta 9-THC and cannabidiol in the most popular types of cannabis sold on the Dutch market are annually measured, we were able to estimate exposure to Delta 9-THC and cannabidiol. Results: We included 1877 subjects (mean age 23, SD 6.0) who used the same type of cannabis in the majority of the occasions (in >60% of occasions). We found a significant inverse relationship (F(1,1877): 14.577, p<0.001) between cannabidiol content and self-reported positive symptoms, but not with negative symptoms or depression. The estimated effect size of cannabidiol content was small. Conclusion: Although the observed effects are subtle, using high cannabidiol content cannabis was associated with significantly lower degrees of psychotic symptoms providing further support for the antipsychotic potential of cannabidiol. (C) 2011 Elsevier B.V. All rights reserved.