Assuming the study is robust, here is one possible contribution. In the US in 2021, 52 million people reported using cannabis in the previous 12 months. https:/

Assuming the study is robust, here is one possible contribution. In the US in 2021, 52 million people reported using cannabis in the previous 12 months. https://www.samhsa.gov/data/report/2021-nsduh-annual-national-report https://www.samhsa.gov/data/report/2021-nsduh-annual-nationa... A meta analysis from 2020 reports an 'almost 2-point decline in IQ' following frequent or dependent cannabis use in youth. While accepting that family level vulnerability predisposing to IQ decline is possible, the authors conclude this is unlikely to be fully explanatory of the effect. https://doi.org/10.1017/S0033291720005036 https://doi.org/10.1017/S0033291720005036 (Medicine 51, 194–200) As is often the case, definitive conclusions are hard to come by. An earlier study found 'little evidence' to support this 'cannabis effect'. https://www.pnas.org/doi/pdf/10.1073/pnas.1516648113 https://www.pnas.org/doi/pdf/10.1073/pnas.1516648113