according to an article, 60% of 18-30 year olds in north korea take meth

"A source from Yangkang Province told The Daily NK today, “Between students of 14-18, it’s so bad that if you don’t do ‘bingdu’ you are branded a loser. It was only small when it started in 2007, but at this point you would probably find 5 to 7 kids in any class of 30 doing it.”

The source explained that these students first get hold of the drugs by stealing a little bit of their parents’, but then later they pool what money they have to buy it in the market.

They are not able to afford the ‘A-class’ drug that adults take, since it sells for 100 Yuan per gram, instead purchasing a lower purity ‘B-class’ version for half that amount."

full article here http://www.dailynk.com/english/read.php?cataId=nk00100&num=7723

apparently its so they can work more efficiently and not get tired. those crazy NK's.