The effects of the 4/20 cannabis holiday and adult-use cannabis legalization on medical cannabis sales and medical cannabis patient registration in Arizona.

Background: This study examined whether the 4/20 cannabis holiday was associated with increases in medical cannabis sales from licensed dispensaries in Arizona from 2018-2021, and whether adult-use cannabis legalization (the vote in November 2020 and retail sales in January 2021) was associated with declines in medical cannabis sales and in the number of registered medical patients.

Methods: Data came from the Arizona Medical Marijuana Program monthly reports from January 2018-December 2021. The reports show daily sales from licensed medical cannabis dispensaries (i.