By Pat Anson, PNN Editor

The overdose crisis in the United States began long before a spike in opioid prescribing and is likely to last for many more years, according to a new study published in Science magazine.

Researchers at the University of Pittsburgh Graduate School of Public Health looked at nearly 600,000 poisoning deaths in the U.S. from 1979 to 2016 and found a steadily rising number of overdoses caused by “subepidemics” of different drugs, including heroin, cocaine, illicit fentanyl, methamphetamine and prescription opioids. As each subepidemic rose and fell, the drug fueling it was replaced by another substance that can be abused.

“The epidemic of drug overdoses in the United States has been inexorably tracking along an exponential growth curve since at least 1979, well before the surge in opioid prescribing in the mid-1990s,” said senior author Donald Burke, MD, Pitt Public Health dean and UPMC-Jonas Salk Chair of Global Health. 

“Although there have been transient periods of minor acceleration or deceleration, the overall drug overdose mortality rate has regularly returned to the exponential growth curve. This historical pattern of predictable growth for at least 38 years strongly suggests that the epidemic will continue along this path for several more years.”

Burke and his colleagues say the type of drug and the demographics of those who die from overdoses has fluctuated over the years. When the use of one drug waned, another drug replaced it, attracting new populations from different geographic regions.

When plotted on a map, certain drugs dominate different areas. Almost every region in the country is a hot spot for overdose deaths from one or more drugs. Heroin and cocaine primarily impact urban populations, while prescription opioids and methamphetamine skew a bit more rural. Cocaine increased death rates for black men, while heroin raised the death rates for younger whites and older blacks.

To be successful, researchers say overdose prevention efforts must extend beyond control of individual drugs. The current subepidemic of drug deaths caused by illegal and legal opioids will likely to be replaced by something else.

“The recent historical variability with which some specific drugs have waxed and waned makes predictions about the future role of specific drugs far more uncertain. Indeed, it is possible that in the future, the drug overdose epidemic may be driven by a new or heretofore obscure psychoactive substance,” Burke warned. 

Click on the video below to see a chart of the different subepidemics and how they align to form an exponential growth curve:

Technological factors fueling the epidemic include enhanced communication methods (smartphones and the Internet), faster supply chains (FedEx and UPS) and underground drug manufacturing that increased the supply of drugs while lowering their cost. Socioeconomic factors such as unemployment, lost social connections and lack of healthcare may also be creating a climate of despair that leads to drug abuse. 

“Understanding the forces that are holding multiple subepidemics together into a smooth exponential trajectory may be important in revealing the root causes of the epidemic, and thisunderstanding may be crucial to implementation of prevention and intervention strategies,” Burke said. 

“Evidence-based public health responses have contained past epidemics. If we understand and address these root causes at the same time that we take on the opioid crisis, we should be able to curb the epidemic for good."