Opioid overdose deaths doubled in the U.S. between 2015 and 2016. According to the CDC’s Morbidity and Weekly Report released Thursday, March 29, the number of fatal overdoses in 31 states and the District of Columbia increased from 2015 to 2016 despite greater awareness.

“Deaths involving synthetic opioids increased in every subgroup examined,” the CDC researchers report.

The study found that synthetic opioids were responsible for 66% of all fatal overdoses in 2016. For every 100,000 Americans, 13.3 died due to fatal overdose of opioids. That’s a 27.9% increase from 2015.

The death rate from fatal overdose increased 56.1% for non-Hispanic blacks, 36.4% for Asian and Pacific Islanders, 32.6% for Latinx, 25.9% for whites, and 14.9% for Native Americans.

Despite public awareness of the opioid epidemic, exposure to synthetic opioids such as heroin in urban areas may be a key component in the rising death rates. The introduction of fentanyl on the black market is another potential cause.

Compared to the 3 billion tons of hazardous materials that are shipped every year in the U.S., even the smallest amounts of fentanyl are highly toxic. In fact, it may have been an accidental overdose of fentanyl that claimed the life of Prince in 2016.

Excluding methadone, the overall death rate from synthetic opioids between 2015 and 2016 more than doubled.

However, it isn’t only synthetic opioids that are becoming an increasingly deadly problem. There was also an increase as high as 10.6% in American deaths related to prescription opioids.

These numbers are significant in the argument over opioid medications for those suffering from chronic pain. Chronic pain sufferers have stated in the past that other prescription pain medications don’t work as well as opioids for treating long-term pain.

However, a recent study conducted by Dr. Erin Krebs of the Minneapolis Veterans Administration Health Care System at the University of Minnesota found that opioids aren’t any better for treating chronic pain than other medications.

Approximately 80% of the population will experience some form of back pain during their life. Opioid prescriptions are often used to treat chronic back pain such as osteoarthritis.

Dr. Krebs’ study involved 240 veterans suffering from chronic back pain. Half the participants were treated with opioids and half were treated with common over-the-counter medications.

At the beginning of the study, patients thought opioids were more effective than non-opioid medications at treating chronic pain. However, nine months into the study, participants who were treated with non-opioid medications reported less severe pain than those treated with opioids.

“Within a few weeks or months of taking an opioid on a daily basis,” said Dr. Krebs, “your body gets used to that level of opioid, and you need more and more to get the same level of effect.”

Yet the greater the dose of opioid medication, the greater the risk of fatal overdose. It’s for this reason that CDC researchers are advocating for non-opioid pain management.

The use of medication-assisted treatment, or MAT, is also being advocated for. The success rate of methadone treatment for treating opioid addiction ranges between 60% to 90% compared to the 5% to 10% success rate of abstinence-only treatment.

“[Opioids] really don’t have any advantages in terms of pain relief that might outweigh the known harms that they cause,” Dr. Krebs said.