Pretty much everyone knows now that opioids are highly addictive and can be deadly. The drugs, often prescribed by doctors for pain, have become notorious due to an epidemic of costly and dangerous addiction across America. More than 183,000 people died in the United States from opioid use between 1999 and 2015, and millions more live with addiction.

But it took the medical world a long time to wake up to that reality.

While no single factor is to blame for the opioid crisis, a recent correspondence published in The New England Journal of Medicine offers a compelling argument that one short letter published in that same journal 37 years earlier may have played a major roll in sparking and fanning the flames of the crisis. That correspondence downplayed the dangers and addictiveness of prescription opioids for chronic pain.

Only five sentences long, the 1980 missive seems, at first glance, hardly likely to have changed the course of medical history. Here it is:

New England Journal of Medicine NEJM opioid letter 1980
A letter published in the *New England Journal of Medicine* in 1980.

The thrust is simple: Patients with chronic pain are very unlikely to develop an addiction to opioids.

As the authors of the 2017 correspondence point out, the 1980 letter’s writers offered no supporting evidence for their brief claim. But the letter was cited 608 times after its publication, in 439 cases specifically, to support the safety of opioid prescriptions. And those citations spiked after the introduction of the long acting, commercial OxyContin in 1995.

oxyconton chart opioid crisis
A chart tracking citations of the 1980 letter. The dark blue bars represent papers that took the letter's claims at face value or supported them.

Purdue Pharma, which sold OxyContin, agreed in 2007 to pay $600 million in fines for misleading regulators, doctors, and patients about the drug, which has been shown to be addictive in chronic pain patients. Three executives at the company also plead guilty to criminal charges, paying a total of $34.5 million.

The researchers on the more recent letter write, “Our findings highlight the potential consequences of inaccurate citation and underscore the need for diligence when citing previously published studies.”

In other words, researchers need to stop uncritically citing other writing, but rather check the work behind that writing. If they don’t, there can be disastrous consequences.

Photos via NEJM, Getty Images / Spencer Platt