By Cristy Lytal
While Congress considers proposals for federal drug liberalization including legalizing marijuana and decriminalization, USC professor Rosalie Liccardo Pacula is working to inform decisions regarding possible regulations through research.
As an economist who studies addiction and the markets for intoxicating substances, Pacula enjoys the challenge of doing research in this area. Analytically there are challenges, as often, data to build new models or theories is limited. More importantly, though, there is the challenge of understanding the human experience, as motivations for using addictive substances are complex, and persistent misuse often arises due to unique personal, social and economic circumstances, including homelessness, chronic poverty, mental illness and other long-term health problems.
“A lot of the social problems that I deeply care about tend to involve populations struggling with substance misuse or the spillover effects of misuse by a family member,” said Pacula, who is the Elizabeth Garrett Chair in Health Policy, Economics, and Law at the USC Price School of Public Policy and a senior fellow at the USC Leonard D. Schaeffer Center for Health Policy and Economics. “That’s another reason why I find it to be a particularly important area for research.”
Two of her recent studies — one in the American Journal of Health Economics and the other in the American Journal of Preventive Medicine — focus on the regulation of recreational cannabis and the unintended consequences of OxyContin reformulation.
Under-regulation and legislative hurdles
Pacula shared that when it comes to regulating and marketing legal drugs to the American public, there have been many missteps. One of the most publicly recognized missteps was the aggressive marketing of medical opioids — particularly OxyContin.
“I am so frustrated that people are not paying attention to the fact that we still allow pharmaceutical companies and medical device companies to go directly to doctors and market their products,” said Pacula.
“We need the pharmaceutical and medical device companies to go to an independent body. That independent body should assess and test products and then inform the doctors about their efficacy in different populations of patients. You should not have pharmaceutical companies directly informing doctors, as it provides the opportunity for them to misrepresent the efficacy of the product for specific conditions and/or encourage inappropriate prescribing. Most other countries do not allow that.”
The opioid crisis has embroiled Johnson & Johnson and the nation’s three largest drug distributors in thousands of lawsuits, resolving in a $26 billion settlement. States will use this money to provide social services, such as treatment and first responder programs, to address the harms from these addictive substances.

Vaping products have also been under-regulated due to their original introduction as a smoking cessation tool. Until very recently, the Juul e-cigarette sold in the U.S. had three times the amount of nicotine found in the Juul e-cigarettes sold in the U.K., which regulates the contents of e-cigarettes and vaping liquids more closely. And, until just a year ago, vape shops in the U.S. were able to mix their own house blends of flavored liquids for vaping without any federal oversight.
“If we want to have a responsible market for an addictive good, we need to allow government to intervene so that we don’t allow businesses to over-market these highly addictive products, particularly to young people,” said Pacula.
Unfortunately, regulation becomes even trickier when it’s handled on a state-by-state basis. Due to the fact that cannabis has been legalized in several states but not yet at the federal level, the FDA does not have the authority to approve and regulate products, as they would other medicines or even tobacco products. As a result, a vast array of cannabis products have been re-engineered to be far more potent than the weed of the 1970s.
“The cannabis plant of the 1970s had few, if any, harmful effects due to THC [the main psychoactive ingredient in the plant] averaging about 5-7%. But that’s not what’s being sold and produced by the industry today,” said Pacula. “The average potency of the plant has grown four-fold, and we have plant-derived products, such as oils and concentrates, that deliver 80-90% THC. A country can benefit from tax revenue and jobs associated with the cannabis industry without facilitating the sale of such high potency products in the marketplace.”
Pacula explored one consequence of our current state-based cannabis regulation in a recent study titled “Current U.S. State Cannabis Sales Limits Allow Large Doses for Use or Diversion” in the American Journal of Preventive Medicine.
In the study, she and her co-authors calculate that current state sales limits allow customers to purchase between 560 and 2,283 10 mg doses of THC in a single transaction. Not only does this limit vary tremendously by state, but it also represents an amount of THC that exceeds the typical monthly consumption of the average daily user — in a single purchase — facilitating diversion of doses sold in the legal market to the black market.
Pacula and her co-authors suggest that states consider implementing stricter sales limits based on THC content, rather than product weight, which would encourage moderate use of the substance and reduce diversion.
The reality of unintended consequences
OxyContin is another drug that has strayed from its origins. Initially, the reformulation of this now notorious substance was intended to stop people from abusing the drug – instead, it pushed users to seek cheap black-market substitutes such as heroin.
But the trouble didn’t stop there.
In “The Evolving Consequences of OxyContin Reformulation on Drug Overdoses” published by the American Journal of Health Economics, Pacula and her colleague David Powell highlight how OxyContin reformulation broadly stimulated the growth of illicit drug markets, contributing to more fatal overdoses involving not only heroin and illicit fentanyl but also other drugs including cocaine and other illicit drugs that started getting mixed with fentanyl.
“The unintended consequences come in when there are close substitutes or when there are inadequate resources to facilitate sustainability of an approach,” said Pacula.
She encourages a nuanced approach that takes into consideration the effects of policies on different types of users along the continuum from initiation to regular use to harmful use to abuse dependence or quitting.
“I look at a policy, and I consider that policy when I cut the data a bunch of different ways: if we’re talking about the youth population, the young adult population, the criminally involved or the socially marginalized population, pregnant women who are a high-risk population, elderly, disabled,” she said.
Some policies apply broadly across the continuum of users, such as taxes on alcohol or tobacco. Other policies are applied more narrowly, such as a seven-day limit on opioid prescriptions for new users or mandates that only require certain types of insurance plans to cover drug or alcohol treatment.
She continued: “I try to see what the differential effects of specific policies are on each of these groups. Are there a lot of new users in this group? Are there a lot of regular users, but not heavy users? Because certain data sets, like household populations, tend not to have a lot of the high-using illicit drug users, it is not always the right population in which to evaluate a policy, particularly if your focus is on the largest consumers. The largest consumers have already fallen out of the household population.”
Family ties and table talk inspiration
Like many researchers who study addiction, Pacula has motivations that are both professional and personal.
“I have an older sibling that became addicted to intoxicating substances at a young age. She was raised exactly like I was, was given the same opportunities, and yet took a very different path,” she said. “It turns out she also suffers from mental illness. So a lot of people doing research in this area usually have a personal connection that gets them engaged in this sort of research.”
Pacula’s family was very engaged in thinking about societal issues. Her father and several other relatives were lawyers, who enjoyed nightly conversations about politics and social justice at the dinner table.
She also briefly considered a career in politics, but after spending a semester at American University in Washington, DC she saw how profoundly economics impacted policymaking. Inspired, Pacula decided to pursue a PhD in economics at Duke University and began doing research about alcohol policy with Professor Philip J. Cook.
She went on to teach and do research, first at the University of San Diego, then at the RAND Corporation for 21 years before joining the faculty at USC in 2019. Today, her research interests broadly encompass the economics of addiction, markets for intoxicating goods, policies targeting these markets, and the delivery and financing of treatment as it relates to opioids, cannabis, alcohol, tobacco and other drugs.
A health-oriented approach
With such a personal connection to this work, it’s no surprise that Pacula orients her research with health outcomes in mind.
“We’ve been criminalizing drug users as a country, but forget the fact that there are aspects of these drugs that are potentially harmful to the user as well as to society. We need to try to figure out what’s the best mix of policies to be constructive rather than reactive,” said Pacula.
The inadequacy of current resources is particularly apparent when it comes to treatment and recovery support. Addiction is a chronic disease that is typically complicated by additional physical and mental health comorbidities. Relapses are a common part of the long-term recovery process.
Pacula asserts that, in every health care system, insurance coverage needs to extend beyond the initial treatment and allow for a personalized approach. For some patients, treatment might mean pharmacological treatments such as buprenorphine for opioid addiction. For others, a treatment plan might focus more on behavioral interventions, which need to be better integrated into the traditional health care system. And for others still, treatment might mean sustained medically-supervised use so as to manage another health issue, such as chronic pain, that cannot be adequately managed through other means.
She points to the growing body of evidence demonstrating the importance of social support in sustaining recovery from addiction.
“The best way to get somebody off of drugs who is using for reasons other than pain management is to give them an incentive to be engaged in an alternative activity with a new social support group that discourages, but does not judge substance use,” said Pacula. “The best way is not to tell them that they’re a criminal and they’re a bad person. We don’t treat alcoholics the way we treat individuals who are addicted to cocaine or heroin.”
Pacula also warns against an “assumption of zero tolerance in order to be clean.” In other words, it’s important to consider harm reduction strategies, such as heroin maintenance, if they enable people to function, go to work, earn income, and be present for their families.
Lastly, Pacula points out that a successful health-oriented approach doesn’t treat addiction as a dependence on a particular substance or behavior.
“As we study the brain and as we have watched the opioid crisis evolve, it’s absolutely clear that addiction is a broader concept,” she said. “So we should not get so focused on treating just opioid addiction. We should be thinking about treating addiction and all of its comorbidities. And in doing that, from a health perspective, we will be far more successful.”