A Nationwide survey showed that heroin users are attracted to the drug not only because it feels good, but because it's cheap. The demographic of heroin users has also dramatically changed over the past 50 years. 

"In the past, heroin was a drug that introduced people to narcotics," principal investigator Theodore J. Cicero, PhD, said in a Washington University in St. Louis news release. "But what we're seeing now is that most people using heroin begin with prescription painkillers such as OxyContin, Percocet or Vicodin, and only switch to heroin when their prescription drug habits get too expensive."

To make their findings the researchers looked at data from over 150 drug treatment centers across the United States. The study encompassed more than 9,000 patients, about 2,800 used heroin as their primary drug.

The research team looked at three key factors in the decision to choose heroin: "lower cost; enjoyment of the high; and the ease with which the drug could be snorted or injected," the news release reported.

"The price on the street for prescription painkillers, like OxyContin, got very expensive," Cicero said. "It has sold for up to a dollar per milligram, so an 80 milligram tablet would cost $80. Meanwhile, they can get heroin for $10."

In recent years reformulation has made OxyContin less accessible for recreational use, causing more users to turn to heroin.

"If you make abuse-deterrent formulations of these drugs and make it harder to get high, these people aren't just going to stop using drugs," Cicero said. "As we made it more difficult to use one drug, people simply migrated to another. Policymakers weren't ready for that, and we certainly didn't anticipate a shift to heroin."

The average heroin user is 23 years old when they do the drug for the first time; most used prescription drugs before switching to heron. Over 90 percent of heroin users are Caucasian and the majority live in the suburbs. In the 1960s most heroin users were male minorities living in the inner city.

"Our earlier studies showed that people taking prescription painkillers thought of themselves as different from those who used heroin," Cicero said. "We heard over and over again, 'At least I'm not taking heroin.' Obviously, that's changed."