a PSC In The News reference, 2012
"National Study: Teen "Heavy" Marijuana Use Up 80 Percent Since 2008" - Wall Street Journal. 05/02/2012.
Lloyd Johnston comments on a 2011 survey finding that 9% of teens admitted smoking marijuana 20-plus times in the prior month, a rate that's increased 42% since 2008. Johnston says declining perception of risk plays a key role in this upturn. And "the fact that perceived risk is still falling portends a further increase in use," he says.