Hypothesis: Emerging Evidence Might Suggest That Increases in Cannabis Use Disorder Following Legalization of Recreational Cannabis Significantly Contribute to Socioeconomic-Dependent Increases in the Prevalence of Autism Spectrum Disorder

A recent report on the prevalence of autism spectrum disorder (ASD) from California describes unprecedented levels of ASD in that population. The data indicate a transition or changepoint in 2015-2016 in which the prevalence of ASD began to accelerate more rapidly after almost a decade of consistent yearly increases. The changepoint is associated strongly with socioeconomic status, being most readily observable in black children and in low-income counties. Herein we propose the hypothesis that legalization of recreational cannabis in late 2016 led to several cultural changes that in turn caused socioeconomic-dependent increases in very frequent cannabis use and/or cannabis use disorder (CUD). CUD is strongly associated with ASD, and we hypothesize that an adverse drug-drug interaction between acetaminophen and a component or components of cannabis may be at play. It remains unknown whether prenatal or postnatal exposures may be more critical, and further work aimed at evaluating very frequent cannabis use and/or CUD and ASD rates in subsets of the population is strongly encouraged. Paradoxically, caution is urged so that work to decrease CUD does not impede ongoing and promising work using cannabis and cannabis-derived products for the treatment of patients with ASD.