How gambling affects the brain and who is most vulnerable to addiction

It has never been easier to place a bet. Once confined mostly to casinos concentrated in Las Vegas and Atlantic City, gambling has expanded to include ready access to lotteries and online games and video games with gambling elements for adults and children.

Sports betting is now legal in 37 states plus Washington, DC, with six more considering legislation, according to American Gaming Association data from early 2023.opens in new window People can gamble around the clock from anywhere and, increasingly, at many ages, including teenagers and even young children who are well below the legal age for gambling.

As access to gambling has expanded, psychologists and other experts have become concerned not just that more people will give it a try, but that more will develop gambling problems. And while it is still too soon to know what the long-term effects will be, evidence is growing to suggest that young people, especially boys and men, are among those particularly vulnerable to gambling addiction—the same demographic most often participating in the newest forms of gambling: sports betting and video game-based gambling.

People in their early 20s are the fastest-growing group of gamblers, according to recent research. And many kids are starting younger than that. Nearly two-thirds of adolescents, ages 12 to 18, said they had gambled or played gambling-like games in the previous year, according to a 2018 Canadian survey of more than 38,000 youth funded by the government of British Columbia (Understanding the Odds, McCreary Centre Society, 2021 [PDF, 1.1MB]opens in new window). Starting young carries a relatively high burden of psychological distress and increased chances of developing problems.

Researchers are now working to refine their understanding of the psychological principles that underlie the drive to gamble and the neurological underpinnings of what happens in the brains of gamblers who struggle to stop. Counter to simplistic assumptions about the role that the neurotransmitter dopamine plays in addictions (Nutt, D. J., et al., Nature Reviews Neuroscience, Vol. 16, No. 5, 2015opens in new window), research is showing variations in the volume and activity of certain areas of the brain related to learning, stress management, and rewards processing that might contribute to problematic gambling.

Understanding what makes certain people vulnerable to developing problems could ultimately lead to better strategies for prevention and treatment, and also elucidate the evolving health impacts of gambling, the consequences of starting young, and even the role that the government should play in addressing those issues.

As it stands, the National Institutes of Health has agencies dedicated to problem alcohol use and drug use, but there are no official efforts aimed at problem gambling, and there are no federal regulations against advertisements for sports betting, said social worker Lia Nower, JD, PhD, director of the Center for Gambling Studies at Rutgers University in New Jersey. That means kids can see ads, often featuring their sports heroes promoting gambling, at any time of day or night. “It’s the wild, wild west with regard to gambling,” Nower said.

Most adults and adolescents in the United States have placed some type of bet, and most do it without problems. But a significant subset of people who start gambling go on to develop gambling disorder, defined in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) as a persistent, recurrent pattern of gambling that is associated with substantial distress or impairment.

Gambling problems, previously called pathological gambling, were considered an impulse control disorder until 2013, when the DSM-5 classified them as an addictive disorder. That made gambling addiction the first, and so far the only, defined behavioral addiction in the clinical section of DSM-5 (with some hints that video gaming disorder might ultimately follow, experts say). Like addictions to alcohol and drugs, gambling addictions are characterized by an increasing tolerance that requires more gambling as time goes on to feel satisfied. People with the disorder can also experience withdrawal that causes irritability when they try to quit.

Over the last 20 years or so, researchers have refined their understanding of how common gambling addictions are and who is most vulnerable. Among adults, the estimated proportion of people with a problem ranges from 0.4% to 2%, depending on the study and country. Rates rise for people with other addictions and conditions. About 4% of people being treated for substance use also have gambling disorder, as do nearly 7% of psychiatric inpatients and up to 7% of people with Parkinson’s disease. An estimated 96% of people with gambling problems have at least one other psychiatric disorder. Substance use disorders, impulse-control disorders, mood disorders, and anxiety disorders are particularly common among people with gambling problems (Potenza, M. N., et al., Nature Reviews Disease Primers, Vol. 5, No. 51, 2019opens in new window).

Vulnerability is high in people with low incomes who have more to gain with a big win, added psychologist Shane Kraus, PhD, director of the Behavioral Addictions Lab at the University of Nevada, Las Vegas. Young people, especially boys and men, are another susceptible group. Up to 5% of adolescents and young adults who gamble develop a disorder. And men outnumber women at a ratio of about 2 to 1 among people with gambling addictions, although there are a growing number of women with the disorder.

Despite concerns, scientists have yet to document a consistent rise in the rates of gambling problems in recent years, said Jeffrey Derevensky, PhD, a psychologist and director of the International Centre for Youth Gambling Problems and High-Risk Behaviours at McGill University. Still, because more people now have access to gambling, evidence suggests that overall numbers of problems appear to have risen, Derevensky said. After Ohio legalized sports betting, for example, the number of daily calls to the state’s gambling helpline rose from 20 to 48, according to the Ohio Casino Control Commission. Other states have reported similar trends.

As evidence accumulates, it is important to examine the risks without overreacting before the data are in, said Marc Potenza, PhD, MD, director of Yale University’s Center of Excellence in Gambling Research. When casinos enter a region, he said, the area may experience a transient bump in gambling problems followed by a return to normal. Given how quickly gambling is evolving with digital technologies, only time will tell what their impact will be. “We don’t want to be overly sensationalistic, but we do wish to be proactive in understanding and addressing possible consequences of legalized gambling expansion,” he said.

After years of studying the psychological effects of video game violence, psychologist James Sauer, PhD, a senior lecturer at the University of Tasmania in Australia, took notice when Belgium became the first country to ban a feature called loot boxes in video games in 2018. Loot boxes are digital containers that players can buy for a small amount of money. Once purchased, the box might reveal a special skin or weapon that enhances a character’s looks or gives a player a competitive advantage. Or it might be worthless.

On a Skype call after the news broke, Sauer, a psychological scientist and coexecutive director of the International Media Psychology Laboratory, talked with his collaborator, psychological scientist Aaron Drummond, PhD, of Massey University in New Zealand, about Belgium’s decision. Because loot boxes represent a financial risk with an unknown reward, Belgian policymakers had categorized them as a form of gambling, and those policymakers were not the only ones. Countries and states that have passed or considered regulations on loot boxes include Australia, the Netherlands, and Hawaii. But those regulations were contentious.

Sauer and Drummond discussed the need for more science to guide the debate. “We were trying to think about how we might contribute something sensible to a discussion about whether these in-game reward mechanisms should or should not be viewed as a form of gambling,” Sauer said.

To fill the evidence gap, the researchers watched online videos of players opening loot boxes in 22 popular and recently released games that had been rated by the Entertainment Software Ratings Board as appropriate for people ages 17 and younger. Nearly half of the games met the definition for gambling, the researchers reported in 2018, including Madden NFL 18, Assassin’s Creed Origins, FIFA 18, and Call of Duty: Infinite Warfare (Nature Human Behaviour, Vol. 2, 2018opens in new window). Among the criteria for qualifying as gambling was an exchange of real money for valuable goods with an unknown outcome determined at least partly by chance. Purchased objects had value that gave an advantage in the game and sometimes could be sold or traded to others for real money.

Loot boxes tap into the same psychological principles that draw people to slot machines, Sauer said. They may deliver a big payoff, but payoffs come at random intervals. Unlike rewards given after every repetition of a behavior, this type of variable ratio reinforcement, or intermittent reinforcement, exploits a cognitive distortion that makes a player or gambler view each loss as one step closer to a win and can lead to very rapid adoption of a behavior that can then be hard to extinguish, Sauer said. Animals exhibit the same patterns. “They feel sure that the reward is coming, but they can’t know when, so they keep repeating the behavior,” he said. “They continue even as rewards become less and less frequent and even stop entirely.”

After establishing that loot boxes, which generate billions of dollars in revenue for video game companies, are often in fact a type of gambling, studies by Sauer’s group and others since then have shown that people who spend more on loot boxes are often at higher risk of developing gambling problems, and that the connection is strongest in adolescence. Scientists are now working to untangle the question of whether buying loot boxes can cause gambling addictions, and at least some evidence supports this kind of gateway idea.

In one survey of 1,102 adults in the United Kingdom, about 20% of gamblers said that loot boxes were their first introduction to gambling and that their experiences with the game rewards made them think that other forms of gambling could be fun, according to a 2022 study (Spicer, S. G., et al., Addictive Behaviors, Vol. 131, No. 107327, 2022opens in new window). More than 80% of them had started buying loot boxes before they were 18. More recently, Canadian researchers surveyed hundreds of young adult video gamers at two time points, 6 months apart. Among those who were not gamblers when the study started, dozens went on to gamble over the course of the study, they reported in 2023, suggesting that loot boxes had opened the gambling floodgates (Brooks, G. A., & Clark, L., Computers in Human Behavior, Vol. 141, No. 107605, 2023opens in new window).

But the relationship can also go the other way. People who already gambled, the Canadian researchers found, spent more on loot boxes. And in the U.K. research, about 20% of people who started out with other types of gambling migrated to loot boxes—the same proportion that went in the other direction. Figuring out how loot boxes and gambling behavior influence each other remains a work in progress. “We just don’t have the data yet to understand the long-term consequences,” Sauer said.

Also contentious is the question of how loot boxes affect mental health. Sauer’s group has found a link between spending on loot boxes and severe psychological distress (Scientific Reports, Vol. 12, No. 16128, 2022opens in new window), while other research has failed to find the same association. Because kids are increasingly being exposed to gambling, it is an important question to sort through. “Some researchers have argued,” Sauer said, “that if we don’t want kids engaging with bona fide gambling behaviors, maybe we want to be wary about kids engaging with these...gambling-like reward mechanisms.”

Loot boxes are not the only avenue to gambling for kids. Online games that simulate gambling without financial risk are often available to very young children, said Derevensky, who once watched a young girl play a slot machine game on a tablet installed in an airport waiting area. She was earning points, not real money, and loving it. “She’s winning, and she’s saying to her dad, ‘I can’t wait until I play it for real,’” he said. “She must’ve been no more than 6 years old.”

By adolescence, about 40% of people have played simulated gambling games, studies show. These games often involve more winning than their real-world equivalents, Derevensky said. And that playful introduction without financial stakes can spark an interest. Work by his group and others has shown that teens who play simulated gambling games for points are at higher risk of having gambling problems later on (Hing, N., et al., International Journal of Environmental Research and Public Health, Vol. 19, No. 17, 2022opens in new window).

Seeing parents, siblings, or other members of the household gamble also normalizes gambling for kids, making them more likely to engage in gambling and other risky behaviors, including alcohol and drug use, Nower has found in her research (Addictive Behaviors, Vol. 135, No. 107460, 2022opens in new window). And the earlier kids get exposed to gambling through online games and other avenues, studies suggest, the more severe their gambling problems are likely to be later on (Rahman, A. S., et al., Journal of Psychiatric Research, Vol. 46, No. 5, 2012opens in new window).

“Kids as young as preschool are being bombarded with requests to buy things in video games,” Nower said. “A lot of kids move from betting on loot boxes in video games to playing social casino games that are free and then triage them to pay sites. You can’t really tell gambling from video gaming anymore. There’s so much overlap.”

To understand why early exposure makes a difference, and why a subset of people develop gambling addictions, some scientists have been looking to the brain.

Studies have linked gambling disorders to variations in a variety of brain regions, particularly the striatum and prefrontal cortex, which are involved in reward processing, social and emotional problems, stress, and more. Some of these differences may be attributable to genetics. Twin studies and modeling work suggest that genes explain half or more of individual differences with gambling problems, specifically.

In people with gambling disorders as well as substance use disorders, a meta-analysis found that several studies showed less activity in the ventral striatum while anticipating monetary rewards (Luijten, M., et al., JAMA Psychiatry, Vol. 74, No. 4, 2017opens in new window). Along with other findings, those results suggest that this part of the brain contributes to impulsive behaviors for people with gambling problems.

Among other emerging insights, people with gambling problems also have smaller volumes in their amygdala and hippocampus, two regions related to emotional learning and stress regulation. Brain research might help explain why teenagers are particularly susceptible to gambling, Potenza said, including the observation that different parts of the brain mature at different rates in ways that predispose teenagers to gambling and other risk-taking behaviors. The prefrontal cortex, which regulates impulsivity and decision-making, is particularly late to develop, especially in boys.

Parsing out the details could lead to new treatments, Potenza said. For example, he and colleagues stimulated the prefrontal cortex of people with problematic gaming behavior and found improvements in their ability to regulate cravings and emotions (European Neuropsychopharmacology, Vol. 36, 2020opens in new window). The U.S. Food and Drug Administration has begun approving neuromodulatory approaches for using targeted brain stimulation to treat psychiatric conditions, including addictions, that could eventually help people with gambling problems, Potenza said.

New strategies for treatment would be welcome, experts say, as gambling is a particularly tricky addiction to treat, in part because it is easy to hide. As many as 90% or more of people with gambling problems never seek help (Bijker, R., et al., Addiction, Vol. 117, No. 12, 2022opens in new window).

For now, cognitive behavioral therapy is the most common form of treatment for gambling addiction, Nower said, and identifying pathways can tailor therapy to particular needs. She has proposed three main pathways that can lead to gambling problems (Addiction, Vol. 117, No. 7, 2022opens in new window). For one group of people, habitual gambling pushes them to chase wins until they develop a problem. A second group comes from a history of trauma, abuse, or neglect, and gambling offers an escape from stress, depression, and anxiety. A third group may have antisocial or impulsive personalities with risk-taking behaviors.

For young adults who have grown up with video games and online gambling games, sports betting is the newest frontier—for both gamblers and researchers interested in understanding the consequences of early exposure to gambling.

Now legal in many states, the activity has exploded in popularity. An estimated 50 million people were expected to bet some $16 billion on the Super Bowl this year, according to the American Gaming Association, more than double the amount wagered the year before. (Official numbers are not yet available and are usually an underestimate because of “off the books” betting, Nower said.) At its peak, according to news reports, the betting platform FanDuel reported taking 50,000 bets per minute. Billions more were expected to be bet on March Madness.

Sports bettors trend young: The fastest-growing group of sports gamblers are between 21 and 24 years old, according to an analysis by Nower’s group of data from New Jersey, which legalized sports gambling in 2018. Compared with other kinds of gambling, the in-game betting offered during sports games is highly dependent on impulsivity, Nower said. There are opportunities to place bets during the game on everything from who will win the coin toss to which quarterback will throw 100 yards first to how long the national anthem will last. And impulsivity is particularly common in younger people and among sports fans caught up in the emotion of a game, Nower said.

Researchers are still collecting data to see if sports betting is causing a true surge in gambling problems, said Kraus, who is working on a longitudinal study of sports bettors that is following about 4,000 people over a year to see who is most likely to go from betting on a game to having problems with gambling. His group just collected their third wave of data and will be writing up a paper on their results in the coming months. “We’re going to be riding on this issue for years,” he said.

Early signs from Nower’s research in New Jersey suggest that people who engage in sports betting appear to develop gambling problems at particularly high rates and are at higher risk for mental health and substance use problems compared with other kinds of gamblers. About 14% of sports bettors reported thoughts of suicide and 10% said they had made a suicide attempt, she and colleagues found in one New Jersey study.

“Risk-takers who like action can get really involved in sports wagering,” Nower said. “Because of gambling on mobile phones and tablets, there’s no real way to keep children from gambling on their parents’, friends’, or siblings’ accounts. And they’re being bombarded with all these advertisements. This is a recipe for problems among a lot of young people.”

It takes time for a gambling problem to develop, and simple steps can interrupt the progression for many people, Kraus said. That might include placing a limit on how much they are going to spend or setting an alarm to remind them how long they have been gambling.

Education before people try gambling would help, Derevensky said, and plenty of prevention programs exist, including interactive video games designed by his group. But kids do not often get access to them. Teachers are not monitoring lunch tables for gambling activity, Nower said. And administrators are not screening for problems. Derevensky recommends that parents talk with kids about loot boxes and other gambling games and explain the powerful psychological phenomena that make them appealing.

“We educate our kids in our school systems about alcohol use, drug use, drinking and driving, and unprotected sex,” Derevensky said. “It’s very difficult to find jurisdictions and school boards that have gambling prevention programs.”