This week a presidential commission and the Justice Department sounded the alarm about recent increases in opioid-related deaths. One of the most striking features of this problem is that heroin-related deaths have been rising faster than heroin use since 2010, which means heroin use is becoming more dangerous, thanks partly to adulteration with fentanyl, a synthetic narcotic that is roughly 40 times as potent. Drug warriors claim that development is driven by consumer demand because addicts are always looking for a better high. New research reported in The International Journal of Drug Policy (IJDP), which recently devoted a special section to "U.S. Heroin in Transition," tells a different story. The IJDP articles implicate the war on drugs in making heroin more hazardous, but they also provide reasons to hope that harm-reduction policies can mitigate that effect.

According to the official narrative, intravenous drug users seek out fentanyl-fortified heroin, notwithstanding the substantial risk of a fatal overdose, because they prefer its psychoactive effects. "The users know they could die," a DEA official told the Worcester Telegram & Gazette in 2014. "They're chasing the dragon. They're looking for the ultimate high." Last year a vice cop in East Providence, Rhode Island, told a local paper "heroin cut with fentanyl gives the user a more intense high," and addicts "want that ultimate high, taking them right to the edge." A few months later, a DEA agent told the New Haven Register "the users know that they could die from taking this heroin," but "they want the ultimate high," so they ignore the risk.

Brown University medical anthropologist Jennifer J. Carroll and her collaborators interviewed 149 opioid users in Rhode Island and found very little support for such claims. "Our findings directly contradict this narrative," they report in their IJDP article. "Interviewed heroin users overwhelmingly indicated that they prefer to avoid fentanyl-contaminated heroin whenever possible….When they do encounter fentanyl-contaminated heroin, many users report greatly disliking and often fearing the unpredictability of its effects."

The initial effects of fentanyl are more intense than heroin's, but not necessarily in a good way. The interviewees described the experience as overwhelming and incapacitating, and "a general consensus emerged that the effects of fentanyl are distinctly uncomfortable or distressing," with many users describing an unpleasant "pins and needles" sensation in their faces and limbs. Another drawback of injected fentanyl is that its effects last only a half-hour to an hour, compared to four to five hours for heroin.

And then there is the risk of sudden death. "The high potency of fentanyl means that only a minuscule amount (less than 2 mg, the equivalent of two grains of salt) can lead to overdose and death," Brown epidemiologist Brandon Marshall and his co-authors note elsewhere in the same issue of the IJDP. They add that "fentanyl causes rapid and more profound respiratory depression than other opioid analgesics, which significantly narrows the window of opportunity for reversal with naloxone," an opioid antagonist used to treat overdoses. An Australian study found that "the overall risk for fentanyl-related overdose was nearly 4.5 times higher than risk for overdose with other opioids."

Contrary to the accounts of cops and DEA agents, the Rhode Island opioid users interviewed by Carroll and her colleagues did not blithely dismiss this risk. "Participants who were aware of fentanyl universally described it as dangerous and potentially deadly," Carroll et al. write. "People are dropping like flies," one heroin user said. "I don't want to die," said another, explaining why he buys heroin only from a dealer he trusts not to sell him fentanyl-laced powder. Others said they try to avoid fentanyl and take "test hits"—small trial doses—whenever they suspect it is present. "Among illicit opioid users in Rhode Island," Carroll et al. conclude, "known or suspected fentanyl exposure is common, yet demand for fentanyl is low."

In a legal market, such a mismatch would be puzzling. But it is common in black markets, where consumers often get something other than what they really want or think they are getting and have no legal recourse when it happens. Furthermore, as Northeastern University law professor Leo Beletsky and Corey Davis of the Network for Public Health Law point out in another IJDP article, prohibition encourages drug traffickers to favor less bulky, more potent products—a tendency that Richard Cowan, former national director of NORML, dubbed the Iron Law of Prohibition.

During alcohol prohibition, for instance, the market shifted from beer and wine to distilled spirits. "The potency of alcohol products during Prohibition is estimated to have risen by more than 150% relative to pre-Prohibition and post-Prohibition periods," Beletsky and Davis write. From the perspective of drug traffickers who want to maximize the number of doses they can transport in a single package, fentanyl has obvious appeal, especially since it can be synthesized from readily available raw materials and does not depend on growing and harvesting crops.

The emergence of fentanyl and its analogues as common heroin additives or substitutes is the latest wrinkle in a progression that began when the government cracked down on nonmedical use of narcotic painkillers. Restrictions on painkillers pushed opioid users toward heroin, which was cheaper and more readily available but also more dangerous because of its unpredictable purity. "I used to take just the pills, and then I started doing dope, the heroin, only when I could get it, when it was cheaper," one opioid user told Carroll's team. "But I don't prefer it because you never know what you're getting. It's scary, so I'm more into pills."

She is right to be scared, as University of Calgary toxicologist Scott Lucyk and Lewis Nelson, a professor of emergency medicine at Rutgers, point out:

For prescription drug abusers who are used to using prescription opioids with known constituents and concentrations, the use of heroin with its unpredictable purity and potential for adulteration creates significant problems. Not surprisingly, the risks of death related to prescription opioid misuse compared to heroin use are not the same. In 2014, 10.3 million people used prescription pain relievers non-medically as opposed to 914,000 people who used heroin. Despite a greater than 10-fold difference in number of users, the risk of death from heroin is much greater.

The CDC attributed 18,893 deaths to opioid analgesics in 2014. It attributed 10,574 to heroin, which was used by less than a tenth as many people. By that measure, heroin was more than five time as dangerous.

The increased prevalence of fentanyl in black-market heroin has magnified the danger. "Heroin fluctuation in purity is a known overdose risk," write University of British Columbia internist Nadia Fairbairn and her co-authors in an article about naloxone, "and the presence of illicit synthetic opioids contaminating the heroin supply has led to a particularly erratic 'street dope' market that multiplies this risk. People who use heroin are potentially exposed to large variations in drug potency depending on the extent of adulteration with synthetic opioids, thus increasing overdose risk."

As Beletsky and Davis note, "These increases in harm were as predictable as they are disastrous." In fact, they say, "The iatrogenic risk to the health of people who use drugs was not just foreseeable, but in some cases directly foreseen by policymakers." They quote Carrie DeLone, Pennsylvania's former physician general, who recently confessed that "we knew that this was going to be an issue, that we were going to push addicts in a direction that was going to be more deadly." Her justification: "You have to start somewhere."

Beletsky and Davis are rightly appalled by DeLone's attitude, saying, "This statement is emblematic of the belief that decisive action is more important than reducing overall societal harm. While seemingly widespread, this sentiment is inimical to…public health, scientific, and ethical norms." But making drug use more dangerous is arguably one of the ways prohibition works as intended, since it helps scare people away from illegal intoxicants. Conversely, making drug use safer defeats the purpose of prohibition by reducing that deterrent, which is why Maine Gov. Paul LePage vetoed a bill making naloxone more readily available. He complained that "creating a situation where an addict has a heroin needle in one hand and a shot of naloxone in the other produces a sense of normalcy and security around heroin use that serves only to perpetuate the cycle of addiction."

That mindset is notably absent from the contributions to this special issue of the IJDP. "Without serious, sustained efforts to address the direct and root causes non-medical opioid use, intensive supply suppression efforts that brought us fentanyl will continue to push the market towards deadlier alternatives," Beletskly and Davis write. "We must shift the focus from supply reduction to demand and harm reduction." In their article about the harm-reducing potential of the online drug "cryptomarkets" exemplified by Silk Road and its successors, independent researcher Michael Gilbert and University of North Carolina epidemiologist Nabarun Dasgupta argue that "public health and safety strategies should not focus on how drugs make their way to consumers to the exclusion of inquiry into how we can protect those consumers from preventable adverse outcomes."

The IJDP contributors discuss several ways to do that. In addition to wider distribution of naloxone, which is especially important in light of how quickly fentanyl can cause life-threatening respiratory depression, they mention increased access to buprenorphine-based treatment, peer-based recovery programs, Good Samaritan laws that protect bystanders from criminal charges when they call for help in response to an overdose, drug testing services that can alert users to the presence of dangerous adulterants such as fentanyl, education that focuses on harm reduction techniques, safe injection facilities where people can use drugs in a sanitary environment under medical supervision, and heroin by prescription.

These measures vary widely in their practical promise and their political viability. What they have in common is a humane commitment to reducing the harm associated with opioid use, including the harm caused by prohibition.