So as painkiller overdoses leveled off at about 16,000 in recent years, heroin deaths skyrocketed from just over 3,000 in 2010 to more than 8,200 in 2013, according to CDC data. Though all heroin users didn't necessarily start with painkillers, it's the transition from painkillers to heroin, Humphreys and other experts say, that led to the recent dramatic spike in heroin abuse.
Below is a link to a Vox article that presents evidence regarding the above quote, and the reason there's a heroin epidemic in the US is because of the overly aggressive (lobbied, and punished for dishonesty in marketing) pharmaceutical industry pushing opiate drugs. Now, with the crackdown on pills, there are wide, wide swaths of the US population who've gone from pills to the horse:
http://www.vox.com/2015/10/1/9433099/opioid-painkiller-heroi...