“Heroin use has increased rapidly across the U.S. and throughout society,” said CDC director Dr. Tom Frieden during a press conference. “With that increase we are seeing a dramatic rise in deaths.”Addiction to prescription pain killers may be fueling some of the rise in heroin use. As TIME has reported, people who are addicted to painkillers may make the switch to heroin since it’s cheaper, doesn’t require a prescription, and offers a similar high. According to the CDC, those who are addicted to prescription opioid painkillers are 40 times more likely to be addicted to heroin. “Most heroin users have a history of nonmedical use of prescription opioid pain relievers, and an increase in the rate of heroin overdose deaths has occurred concurrently with an epidemic of prescription opioid overdoses,” the study authors write.