Clouding Up Cognition? Secondhand Cannabis and Tobacco Exposure Related to Cognitive Functioning in Youth

BACKGROUND: Increasing legalization of cannabis, in addition to longstanding rates of tobacco use, raises con-cerns for possible cognitive decrements from secondhand smoke or environmental exposure, although little research exists. We investigate the relation between cognition and secondhand and environmental cannabis and tobacco exposure in youth.METHODS: The Adolescent Brain Cognitive Development (ABCD) Study year 2 follow-up (N = 5580; 48% female) cognitive performance and secondhand or environmental cannabis or tobacco exposure data were used. Principal components analysis identified a global cognition factor. Linear mixed-effects models assessed global cognition and individual cognitive task performance by cannabis and/or tobacco environmental exposure. Sociodemographics and other potential confounds were examined. p values were adjusted using the false discovery rate method.RESULTS: Global cognition was not related to any exposure group after testing corrections and considering con-founds. Beyond covariates and family-and site-level factors, secondhand tobacco was related to poorer visual memory (p = .02), and environmental tobacco was associated with poorer visuospatial (p = .02) and language (p = .008) skills. Secondhand cannabis was related to cognition, but not after controlling for potential confounders (p . .05). Environmental cannabis was related to better oral reading (p = .01). Including covariates attenuated effect sizes. CONCLUSIONS: Secondhand tobacco exposure was associated with poorer visual memory, while environmental tobacco exposure was related to poorer language and visuospatial skills. Secondhand cannabis was not related to cognition after controlling for sociodemographic factors, but environmental cannabis exposure was related to better reading. Because, to our knowledge, this is the first known study of its kind and thus preliminary, secondhand cannabis should continue to be investigated to confirm results.

Automated summary

This study investigates the relationship between cognition and secondhand cannabis and tobacco exposure in youth. The findings suggest that secondhand tobacco exposure is associated with poorer visual memory, while environmental tobacco exposure is related to poorer language and visuospatial skills.