The psychological bias keeping U.S. drug laws out of step with science

Americans tend to support the legality of substances that are already legal and oppose legalizing those that are currently outlawed, more than the drugs’ actual harms would predict. A new study published in Nature Human Behaviour suggests that existing drug laws themselves may shape public attitudes, helping keep regulations out of step with expert assessments of harm. Giving people expert harm ratings reduced their support for legal alcohol and tobacco but did little to change views on less harmful illegal drugs.

The researchers use the term status quo bias in a specific sense: the idea that a substance’s current legal status shapes how the public perceives it. Because most people have little firsthand experience with most drugs, the law itself, along with how media portray a substance, can serve as a cue for what is safe, normal, or morally acceptable. The authors distinguish this from the more familiar psychological concept of the same name, which refers to a general preference for sticking with existing options.

Drug regulations in the United States often clash with medical science. For instance, a 2010 evaluation by addiction experts found that legal substances like alcohol and tobacco cause substantially more physical and social damage than several banned substances, including psychedelics and MDMA (commonly known as ecstasy).

At the same time, politicians are not simply ignoring voters when they maintain these laws. Over the past decade, more than 25 statewide ballot measures on drug regulation have given more than 100 million Americans the chance to vote on these questions. Public sentiment has also been shifting: a 2023 time-series analysis found that Americans’ overall mood toward drugs has grown more liberal since the late 2000s.

That raises a puzzle: if citizens generally want sensible policies that minimize harm, why do they endorse drug laws that contradict expert harm assessments? A 2019 review of criminal justice research argued that public opinion does influence policies such as incarceration rates, which makes the question of how those opinions form all the more pressing.

Free daily newsletter

Bence Hamrak, a research fellow at the European University Institute in Florence, and Gabor Simonovits, an associate professor at Central European University in Vienna and researcher at the ELTE Centre for Social Sciences, set out to explore this puzzle. They argue that criminalizing a drug can concentrate its use among marginalized groups, leaving most people to learn about it mainly through media coverage focused on addiction and crime rather than through firsthand experience. People may then blame the substance or its users for problems partly created by criminalization itself, strengthening support for keeping the ban.

“Drugs with similar harms are regulated very differently: some are available with prescription, while others are punished and might carry prison sentences,” Hamrak and Simonovits told PsyPost. “These regulatory extremes have detrimental effects for society and the individuals, as the opioid epidemic or the mass incarceration show. Experts have long recognized this mismatch, but policies remain largely misaligned. We asked whether public opinion is part of the explanation for bad policies.”

Because more drug policy is now decided directly through ballot measures, the authors reasoned that public opinion could play a direct role in shaping these laws. “Surprisingly, we found that policies largely match public opinion,” the researchers explained. “So, we realized that the real question is how people form their views about drug harms.”

To test this idea, the researchers first conducted a survey of 2,016 American adults recruited through the online panel provider Lucid Theorem, using census quotas to match the national population by age, gender, race, ethnicity, and region. Participants first indicated whether they were familiar with 13 psychoactive substances that vary in legal status: alcohol, aspirin, tobacco, cannabis, codeine, Xanax, Ritalin (a prescription stimulant), cocaine, heroin, LSD, MDMA, methamphetamine, and psilocybin (magic mushrooms). For each familiar substance, respondents stated whether recreational use should be legal or illegal, and if illegal, whether use should be treated as a decriminalized offense, a misdemeanor, or a felony carrying prison time.

The researchers compared these public opinions against a standardized 0 to 100 harm scale derived from addiction medicine experts, which ranks drugs based on physical organ damage, addiction potential, and social consequences. Across the 13 drugs, the negative correlation between expert harm ratings and public support for legalization was not statistically significant (r = −0.54, p = .06). Respondents strongly favored the legality of high-harm legal drugs over low-harm illegal ones; for instance, support for alcohol being legal was 71.1 percentage points higher than support for MDMA, even though experts rate alcohol as more harmful overall.

To measure how people would judge these substances without the baggage of their real-world names and legal histories, the same participants completed an experiment involving hypothetical “off-brand” drugs. Respondents were asked to imagine themselves as regulators evaluating five newly discovered substances, each described with randomly assigned attributes: physical harm (0 to 100), psychological harm (0 to 100), source (natural, semisynthetic, or synthetic), medical utility (existing medical use, ongoing research, or no medical use), and neurological effect (stimulant, depressant, or psychedelic).

Using statistical models based on how participants judged these randomized profiles, the authors calculated the predicted public support for an unnamed, off-brand version of each of the 13 real drugs. The authors treat the gap between support for a real drug and its off-brand twin as a measure of status quo bias.

For substances that are federally legal for recreational or over-the-counter use, support for the real drugs was much higher than for their off-brand profiles, with a median gap of 39.3 percentage points. Specifically, support for the real named substance exceeded its anonymous counterpart by 62.4 percentage points for alcohol, 39.3 percentage points for tobacco, and 23.8 percentage points for aspirin.

A similar positive gap appeared for cannabis (23.0 percentage points), which is legal for recreational use in about half of U.S. states, as well as for prescription drugs like Xanax and Ritalin (ranging from 12.5 to 28.8 percentage points), though codeine was an exception (−8.2 percentage points). For illegal drugs, the pattern reversed: people supported real illegal drugs at a median of 12.6 percentage points less than their unnamed equivalents. Support dropped by between 7.8 and 19.4 percentage points when respondents evaluated real psilocybin, LSD, heroin, cocaine, and MDMA rather than anonymous substances with identical harm profiles, with methamphetamine being the lone exception (+3.1 percentage points).

In an exploratory analysis, the researchers also examined views on prison sentences. For five of the illicit drugs (psilocybin, LSD, MDMA, cocaine, and heroin), participants were 5.5 to 25.5 percentage points more likely to favor felony incarceration when the drug was named than when evaluating its anonymous counterpart. Without the influence of real-world labels, a majority of participants opposed legalizing almost any of the substances apart from low-harm painkillers, yet a majority also opposed felony prison sentences for most of the unnamed illicit drugs.

“When the effect of the status quo is removed in our experiment, citizens seem to be more restrictive about legalization but also more liberal about punishment than current policies,” Hamrak and Simonovits noted. “At the same time, for most experimental substances the majority did not favor prison sentences either, even for harmful drugs. This suggests that without the biasing force of the status quo, the public could correct policy failures in both access and punishment.”

In a further exploratory analysis of how participants evaluated the unnamed hypothetical drugs, the researchers found that people paid close attention to harm. Compared to a hypothetical drug with high physical harm like alcohol, an otherwise identical drug with moderate physical harm received 13.6 percentage points more legalization support, and one with low physical harm received 23.6 percentage points more support. Even with harm held constant, however, participants showed a preference regarding what a drug does to the brain, favoring depressants by 14.5 percentage points over psychedelics.

Because citizens prioritized harm when judging unnamed drugs, the authors conducted a second experiment with 3,037 new American respondents to test whether correcting people’s misconceptions about real drugs would reduce status quo bias. Focusing on seven substances (alcohol, tobacco, Xanax, cannabis, cocaine, MDMA, and LSD), the researchers first measured how dangerous participants thought these drugs were compared to expert ratings. Respondents tended to underestimate the harms of legal drugs, rating alcohol 17.4 points lower on the 100-point scale than experts do, and overestimate the dangers of illegal drugs, rating MDMA 20.6 points higher than the expert score.

The researchers then randomly provided participants with the true expert physical and psychological harm scores for one of the seven drugs before asking whether it should be legal. Receiving accurate harm facts reduced support for the legality of alcohol by 17.7 percentage points and lowered support for tobacco by 12.9 percentage points compared to the uninformed control group. Providing harm facts also lowered support for the prescription drug Xanax to a level below that of its off-brand version.

Correcting misconceptions about illegal drugs, however, had almost no effect. Learning the expert harm ratings for cannabis, cocaine, MDMA, or LSD produced small, statistically non-significant changes in support for legalization. Overall, accurate harm information erased an average of 32 percent of the status quo bias for alcohol and tobacco, but only 18 percent for cocaine, LSD, and MDMA.

The authors suggest that this lopsided reaction occurs because opposition to illegal drugs is anchored in more than just health concerns. Stigma and racial prejudices toward the marginalized groups associated with illicit drug use may play a role as well, though the study did not test this.

“Citizens are probably not gullible or ill-intentioned when they support bad policies,” the researchers said. “Our suggested explanation for the original bias is simple: most people have little direct experience with most substances, so how we regulate drugs, and how we portray them, shapes how people think about them. Furthermore, some narratives are stickier than others, especially those tied to social norms about acceptable drug use.”

“And, in our experiment, people disliked psychedelics more than depressants or stimulants, even when their harms were the same,” Hamrak and Simonovits added. “This suggests that deep-seated prejudices and stereotypes may resist even new information. People rely heavily on the status quo for information and guidance for what is right or wrong, and this makes it harder for the democratic process to correct biased policies.”

“More accurate information moves public preferences closer to what a purely harm-based assessment would suggest,” the authors explained. “But even for legal drugs, where the information effect is clear, two-thirds of the status quo bias survives. This suggests that factors other than a lack of information also drive the difference between how people evaluate real and hypothetical drugs. Future research should focus on the cultural norms that sustain people’s preferences for regulating both legal and illegal substances, above and beyond harm.”

There are a few things to keep in mind when interpreting these results. The study relies on expert harm scores that treat a drug’s danger as a fixed property of the chemical itself, which leaves out how a drug is consumed, the dosage, and the user’s environment. In reality, some harms tied to illegal drugs arise from how they are used and who uses them, factors that are themselves shaped by the drugs’ legal status, so even experts struggle to separate a substance’s pharmacological risk from the consequences of its ban.

“It would go too far to say our experiment revealed the ‘true’ public preferences about real-world drugs,” Hamrak and Simonovits cautioned. “We cannot say with full confidence that our hypothetical drugs matched real drugs in everything except the factors shaped by the status quo. Our experiment may have left out other information that also matters for judging drugs objectively.”

“For example, we did not include substance harms to others or to society, such as crime,” the researchers noted. “We left these out because, for these kinds of harm, the effects of the drug itself may be too entangled with the effects of the status quo, such as who uses the drugs, how they are used, or how users behave under different legal contexts.”

Additionally, to help participants picture the hypothetical drugs’ effects, the researchers attached familiar social purposes to them, describing stimulants, for instance, as making users less tired and enhancing productivity. The authors acknowledge these descriptions reflect socially shaped ideas about drug use, though they argue that, if anything, this would have shrunk the measured gap between real and hypothetical drugs, making their estimate of status quo bias conservative.

The study also relied on quota-matched online opt-in panels rather than true probability samples of the U.S. population, and drew its benchmark harm scores from a ranking by a panel of German addiction medicine experts. Finally, the surveys capture a single snapshot in time, leaving open the question of how status quo bias starts to crack when states gradually decriminalize or legalize substances like cannabis and psilocybin over many years.

The study, “Status quo bias drives public support for drug policy in the USA,” was authored by Bence Hamrak and Gabor Simonovits.