Plotted beta estimates from the regression models of age of first use of alcohol, cannabis and tobacco on average daily minutes of screen time (square root transformed) of grade 12 students in Canada from years 1 to 5 (2012-2016) of the COMPASS study. All models controlled for sex, ethnicity, weekly spending money, current substance use, and data collection year. The markers have been replaced with a dash (-) at ages that are not significant at p<0.05.