Heroin Was Responsible for One in Four Overdose Deaths in 2015, Says CDC

The Centers for Disease Control (CDC) released new data Friday that sheds more light on the nation's growing opioid crisis, revealing that 25 percent of all overdose deaths in 2015 were attributed to heroin, a sharp rise from just 8 percent in 1999, CNN reports.

Opioids—heroin, prescription painkillers like oxycodone, or illegal heroin synthetics like fentanyl—were also responsible for the majority of overdose deaths in 2015. The study found that opioids caused 73 percent of all overdose deaths last year, which is up from 57 percent five years ago.

Last year, more people died from heroin and fentanyl overdoses, whereas deaths from prescription opioids decreased from 29 percent in 2010 to 24 percent in 2015. This might be a result of those addicted to prescription drugs switching to more illegal alternatives because they're cheaper or easier to get.

The CDC's numbers echo a sweeping study from the US surgeon general released last November that found that 21 million Americans struggle with substance abuse. It revealed that 50,000 people died of overdoses in 2014 alone, while only 32,744 died in car crashes. In 2015, that number jumped to 52,404, which is the first time US overdose deaths exceeded 50,000, according to Holly Hedegard, co-author of the CDC study.

White House press secretary Sean Spicer acknowledged the country's growing opioid epidemic Thursday by likening it to recreational marijuana use.

"When you see something like the opioid-addiction crisis blossoming in so many states around this country, the last thing we should be doing is encouraging people," Spicer said. "There's a federal law that we need to abide by when it comes to recreational marijuana and other drugs of that nature."

However, evidence actually points to the fact that legal marijuana leads to reduced opioid use. A recent Columbia University study surveyed 18 states and found that the places where medical marijuana is legal, there was an decrease in opioid involvement in fatal car crashes. Additionally, a 2014 study published by JAMA Internal Medicine reviewed ten years' worth of death data and found that overdose deaths were 25 percent lower in states with medical marijuana laws than in those without them.