By Pat Anson, PNN Editor

Two new studies in Massachusetts – one of the states hardest hit by the overdose crisis – highlight the role of multiple substances in most overdose deaths and how limiting the supply of prescription opioids has failed to reduce the number of drug deaths.

Researchers at Boston Medical Center's Grayken Center for Addiction analyzed toxicology reports on nearly 2,250 fatal overdoses involving opioids in Massachusetts between 2014 and 2015. Overdose data in Massachusetts is considered more reliable because it is one of the few states to extensively use toxicology testing.

Only 9 percent of the deaths in Massachusetts involved prescription opioids alone. Most of the overdoses (72%) involved illicit fentanyl or heroin, while one in five (19%) involved a combination of heroin, fentanyl or prescription opioids.