Evaluation of THC-Related Neuropsychiatric Symptoms Among Adults Aged 50 Years and Older A Systematic Review and Metaregression Analysis

Abstract

Experimental administration of delta-9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, but not cannabidiol (CBD), a nonaddictive component, induces transient psychotic symptoms,¹ and regular use of cannabis high in THC is associated with increased risk of psychotic symptoms or disorders and poor outcomes in those with an established psychotic disorder.^2,3 This association is well recognized among young people, the age group most often affected by psychosis. Although use of cannabinoid-based medicines (CBMs) is increasing across all age groups, it remains unclear whether THC-containing CBMs also increase the risk of psychotic symptoms in older adults.^4,5 Hence, we used metaregression analyses to examine any association between THC dose and self-reported neuropsychiatric adverse events (AEs) using data from double-masked, randomized clinical trials (RCTs) investigating CBMs in people aged 50 years or older. We hypothesized that there would be a significant association between THC dose and incidence of neuropsychiatric AEs.