Is the current American drug overdose epidemic an isolated phenomenon? Have other high-income countries experienced similar increases in drug overdose mortality, or are they likely to going forward? A new study published in Population and Development Review addresses these questions.

By examining drug overdose death rates between 1994 and 2015 in 18 countries, Dr. Jessica Ho, of the University of Southern California, found that for over a decade now, the US has had the highest rates of drug overdose mortality among its peer countries. Drug overdose mortality has increased rapidly in the US over the course of the contemporary epidemic, resulting in its dramatic pulling away from other high-income countries.

Drug overdose mortality is now 3.5 times higher on average in the US than other high-income countries. It is over 27 times higher than in Italy and Japan, which have the lowest drug overdose death rates. Between 2003 and 2013, drug overdose mortality increased by 0.73 (men) and 0.26 (women) deaths per 100,000 on average in the comparison countries compared with increases of 5.53 (men) and 4.15 (women) deaths per 100,000 in the US.

The potential remains for drug overdose mortality to increase in other countries in the near future, and similar and troubling signs are already discernible in some countries. “One of the most surprising findings from this study is that while Americans now have the highest drug overdose death rates, this hasn’t always been the case. In the late 1990s, Nordic countries like Finland and Sweden had the highest death rates. The countries that now look like they’re at greatest risk of following in the US’s footsteps are other Anglophone countries like Canada, Australia, and the UK,” said Dr. Ho. “Over time, we’ve seen huge shifts in drug overdose, and we need to pay attention to the factors that contribute to the development and continued persistence of this epidemic in the US and, potentially, whether it spreads to other countries.”