The psychology and brain science of a gambling addiction

Despite the well-known adage "the house always wins", many people still insist on trying their luck. Individual reasons for gambling can be varied and include factors like socializing, entertainment, and thrill-seeking. Of course, some just want to "win big money".¹

Over the years, gambling has shed its reputation as a vice activity and is now widely accepted by society. In 2018, a survey conducted by the Gallup found that 69% of Americans feel that gambling is morally acceptable (this is compared to 58% in 2009).

Futhermore, another 2019 survey by the American Gaming Association revealed that 57% of adults in the US feel that casinos help local economies.

Because of its growing popularity, gambling revenue in the country has been steadily increasing in recent years. Apart from the hit it experienced in 2020 due to the COVID-19 pandemic, 2021 ushered in a quick recovery for the industry and it's expected to hit a new record $44 billion in revenue.² The US also sits at the top of the list in terms of total amount lost by country ($116.9 billion) based on data collected in 2016.³

The dark side of gambling: Addiction

However, behind the fun and games lies a more sinister side of gaming. For a subset of people that gamble, the behaviour becomes something that they're unable to control. And it can lead to other serious problems like bankruptcy, homelessness, and strained relationships.

Since the 1980s, pathological gaming has been recognized as a psychiatric disorder by the American Psychiatric Association (APA). But in the past, it was conceptualized as an impulse-control issue. With advancements in research, it became clear that it has more parallels with drug and alcohol addictions. As a result, it now sits under the addictions category in the APA's Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) and is officially known as "Gambling Disorder".⁴

Some diagnostic symptoms for Gambling Disorder include (but are not limited to):⁵

  • Needing to gamble with more money each time to feel thrilled enough

  • Feeling uneasy or restless when trying to reduce or stop gambling

  • Having persistent thoughts about gambling throughout the day

  • Gambling when feeling down 

  • Chasing one's losses

  • Hiding gambling activity from others

About 1% of the adult US population has a gambling disorder, and this increases to 6-9% for younger people. Other studies have found that men, ethnic minorities, lower-income groups, and unmarried individuals are also at a greater risk of developing an addiction to gambling.⁶ ⁷

While the disorder's prevalence has become clearer over the past decades, experts are still refining their understanding of the factors that lead people to develop problematic gambling behaviour. But what we know so far is that there are some commonalities between the way gambling disorder and drugs impact the brain. 

Disordered gambling affects the brain in similar ways to drugs

The altered mental reward system

In the middle of our brain, sits a group of structures known as the reward pathway. It begins from the ventral tegmental area (VTA) and connects to the nucleus accumbens (which forms part of the ventral striatum).

Whenever we do something enjoyable (whether it's eating chocolate, falling in love, gambling, or taking drugs), the pathway gets activated and releases a brain chemical called dopamine. This is what gives us that rewarding pleasure sensation.⁸

As with many biological processes, our levels of dopamine sit in a delicate balance. Having too much or too little can lead to negative consequences. At the moment, experts agree that there are differences in the reward pathway of pathological gamblers compared to healthy individuals. But the exact explanation of how these differences play out in disordered versus healthy gambling behaviour is still being debated.⁹

The traditional view of addictions draws upon drug addiction models, and hypothesizes that addicted gamblers have a hypoactive reward system. This means that the brain is desensitized to dopamine exposure and needs to seek out more intense stimuli to activate it. This may explain the tolerance symptoms of needing to place increasingly riskier bets to achieve previous highs.¹⁰ In support of this theory, older studies have found that pathological gamblers had significantly less activation in the reward system area of the brain compared to the healthy control group when engaging in simulated gambling games.¹¹

However, other researchers have challenged this view and suggest that the reward system is actually hypersensitive to gambling wins. For example, one group of researchers found greater dopamine release is associated with increased gambling disorder symptom severity.¹² While Parkinson's patients with gambling disorder showed increased dopaminergic response to winning in gambling tasks compared to those without gambling disorder.¹³

The addictiveness of gambling comes from its uncertainty (not necessarily winning)

So how do we make sense of this conflicting evidence? The latest research suggests that the crucial part of untangling these contradictions comes down to distinguishing the reward system's reaction to anticipated reward ("wanting") and the reward itself ("liking").

Interestingly, the greatest reward for pathological gamers may not actually come from winning itself ("liking"). It turns out that the brain releases more dopamine in the moments before a gambling result is revealed ("wanting").¹⁴ In pathological gamblers, "liking" decreases as time goes on, while "wanting" increases.¹⁵

This could explain why we see both a blunted response to winning as shown in older studies, but also the hypersensitive dopamine response to uncertain rewards demonstrated in newer studies.

What this means is that the addiction to gambling becomes independent of how many positive outcomes are experienced. In terms of their brain's response, pathological gamblers are rewarded with dopamine simply because of the uncertainty of playing — not necessarily only when they're winning.¹⁶ ¹⁷

Conversely, losing has even been found to be a motivator for problem gamblers and may contribute to the "chasing loses" phenomenon. One study has found that there were no differences between healthy subjects versus pathological gamblers in dopamine release when they won money in a gambling task. But there was significantly more dopamine release in pathological gamers when they lost compared to the healthy control group.¹⁸

The brain's impaired decision-making abilities

However, the reward pathway only forms one part of our understanding of gambling disorder. What turns the behaviour into a habit (even when it goes against rational judgment) is a more complex process that involves emotions and calculation of risk.

This is where researchers explain that the reward pathway doesn't act in isolation. It's also connected to more "primitive" parts of the brain like the limbic system (emotional brain); along with evolutionarily younger areas like the prefrontal cortex which controls higher-order cognitive functions like planning, impulse-control, and decision making.¹⁹

The prefrontal cortex in particular has been of interest to researchers — as a dysfunction in the area could explain why pathological gamblers make poor risk evaluations.

One group of researchers have found reduced activation through fMRI in the prefrontal cortex area in problem gamblers when performing guessing tasks compared to the normal control group.²⁰ While multiple other studies have demonstrated that they also perform significantly worse in prefrontal cortex-controlled decision-making tasks compared to healthy participants — especially in instances that involve rewards.²¹ ²² ²³

Conversely, preliminary research has also shown that transcranial direct current stimulation to this area of the brain may improve decision making and impulsivity in gambling disorder patients.²⁴

Taken together, these studies suggest that those with problematic gamblers not only persist in the behaviour because they're rewarded with washes of dopamine. The part of the brain that is meant to help them objectively process risk and reward also seems to be impaired. This is what makes it hard for them to stop, even when the situation is not in their favour.²⁵

The gambling experience is designed to keep you playing

What also doesn't help individuals with a propensity for gambling disorder is that the industry has adapted their environment and user experience to cater to the brain's craving for uncertain rewards.      

Prolonging play by extending uncertainty

In the past, winning the jackpot was an all or none scenario where you had to get all the same symbols on a single line. The invention of electronic gaming machines (EGMs), which are digital versions of the game, has changed this scenario to allow for more uncertainty to be incorporated into the game.

With EGMs, more reels can be added, which adds to the total number of possible combinations. And it also allows players to place more bets within a spin, while decreasing the amount of each bet. This multiple-line version of the game has been shown to be much more popular with gamblers.²⁶

Changing the format of the game is intentionally designed for prolonged play. And this effect of extending time on the machine has several benefits to the house. Firstly, it increases their chance of winning, because the house always wins in the long run.

But at a deeper psychological level, it also exposes individuals to more mental rewards of uncertainty. Preliminary studies have indicated that this pattern of play is more likely to lead to problematic gambling compared to other types of gambling like the lottery — even though EMGs may not be as widely played.²⁷ ²⁸

Lastly, it also creates the illusion of winning when they're losing for players. Multiple-line play means that mini-jackpot wins can be issued along the way to encourage them to continue — even though the overall outcome is still a loss. 

Almost winning as part of game design

EMGs also give designers the chance to carefully orchestrate the type of loss that one experiences to influence subsequent gambling. There is a significant difference when we narrowly lose ("near-miss") or clearly lose in gambling. If we take the game of jackpot as an example, a near-miss would be when 3 out of 4 reels were of the same symbol — just 1 reel away from hitting the jackpot.

Studies have shown that such outcomes activate the reward system in the brain a lot more than clear losses.

Crucially, those with gambling disorder are more likely to experience increased activation in this area compared to healthy controls.²⁹ What's even more intriguing is that even though near-misses are extremely frustrating, it motivates people to play for longer.³⁰ ³¹

What about online gambling?

In addition to the digitalization of gaming in casinos, the industry has shifted online to increase its accessibility at any time and place. Because of the nature of this newer form of gambling, experts have been worried about the impact that this will have on the prevalence of pathological gambling.

At the moment, preliminary prevalence studies indicate that the rate of pathological gambling may be higher in internet gamblers compared to land-based gamblers. But researchers also caution that there are too many factors confounding these statistics at the moment. For example, other studies indicate that it's difficult to find exclusively-online gamblers to validate these numbers. Therefore, it's still too early to say whether online forms of gambling increase the risk of gambling disorder.

Nevertheless, public health bodies are still concerned about how this highly accessible form of gambling will impact society — especially on youths growing up as digital natives.³² ³³ With the proliferation of gambling social apps and online marketing, young people are receiving earlier exposure and normalization of the activity compared to previous generations. More long-term studies looking at whether early exposure to gambling increases the risk of harm is warranted — especially if we look to other public health areas like alcohol and tobacco as indicators.³⁴

Barriers to gambling disorder treatment still exist

Despite our better understanding of gambling disorder as an addiction, several barriers to treatment still exist within society and even the clinical community. The widespread belief that pathological gambling is caused by character flaws rather than multiple biopsychosocial factors still exists. And this contributes to the low rate of treatment-seeking in this population — it's estimated that only 10-30% of individuals with gambling disorder will receive treatment in their lifetime.³⁵

It's also less likely to be screened by community-setting practitioners compared to substance-use disorders, making identification difficult. And many also don't have enough knowledge on the topic as more emphasis is usually placed on substance use during training.³⁶

This emphasizes the need for more awareness and prevention campaigns to take place. There have already been calls by the World Health Organization and some countries for gambling disorder to be considered as a public health issue as the social costs are starting to outweigh the economic benefits.³⁷ ³⁸ One 2017 report from Victoria in Australia estimates that the total gross revenue from the gambling industry was A$5.8 billion and tax revenue was A$1.6 billion. On the other hand, social costs far exceeded these amounts at A$7 billion.³⁹

The gambling industry is constantly evolving and is likely to become more accepted and accessible globally. The social and economic effects of pathological forms of gambling are already taking a toll on society. And with its evolving nature, we might see more harm being caused. Governments shouldn't take the risk of adopting a "wait and see" approach in the prevention and treatment of pathological gambling.

  1. Gambling Motives: Application of the Reasons for Gambling Questionnaire in an Australian Population Survey (2015)

  2. U.S. Gambling Revenue To Break $44 Billion Record In 2021 | Forbes

  3. The world’s biggest gamblers | The Economist

  4. How the Brain Gets Addicted to Gambling | Scientific American

  5. DSM­5 Diagnostic Criteria: Gambling Disorder | NCP Gambling

  6. Gambling Disorders | National Center for Responsible Gaming

  7. Shedding Light on Gambling Disorder as an Addiction: A Guide for Practitioners (ATTC Messenger) | Research Gate

  8. Addiction and the brain: The dopamine pathway is helping researchers find their way through the addiction maze (1999)

  9. Nuances of the Reward System in Problem Gambling | Gambling Research Exchange Ontario

  10. Gambling Addiction and the Brain |

  11. Pathological gambling is linked to reduced activation of the mesolimbic reward system | Research Gate

  12. Mesolimbic dopamine release is linked to symptom severity in pathological gambling (2012)

  13. Increased striatal dopamine release in Parkinsonian patients with pathological gambling: a [11C] raclopride PET study (2009)

  14. What motivates gambling behavior? Insight into dopamine's role (2013)

  15. The Iowa Gambling Task and the three fallacies of dopamine in gambling disorder (2013)

  16. Mesolimbic dopamine release is linked to symptom severity in pathological gambling (2012)

  17. Striatal dopamine release codes uncertainty in pathological gambling (2012)

  18. Dopamine release in ventral striatum of pathological gamblers losing money (2010)

  19. Addiction and the brain: The dopamine pathway is helping researchers find their way through the addiction maze (1999)

  20. Pathological gambling is linked to reduced activation of the mesolimbic reward system (2005)

  21. Frontal lobe dysfunction in pathological gambling patients (2002)

  22. Executive function abnormalities in pathological gamblers (2008)

  23. Cognitive Inflexibility in Gamblers is Primarily Present in Reward-Related Decision Making (2014)

  24. Improvement of Impulsivity and Decision Making by Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex in a Patient with Gambling Disorder (2021)

  25. Gambling Addiction and the Brain |

  26. Upping the Reinforcement Rate by Playing the Maximum Lines in Multi-line Slot Machine Play (2015)

  27. Games in the Brain: Neural Substrates of Gambling Addiction (2016)

  28. What motivates gambling behavior? Insight into dopamine's role (2013)

  29. Amplified Striatal Responses to Near-Miss Outcomes in Pathological Gamblers (2016)

  30. Effects of the "near miss" and the "big win" on persistence at slot machine gambling (2001)

  31. Gambling Near-Misses Enhance Motivation to Gamble and Recruit Win-Related Brain Circuitry (2009)

  32. Online Gambling Addiction: the Relationship Between Internet Gambling and Disordered Gambling (2015)

  33. Isolating the impact of specific gambling activities and modes on problem gambling and psychological distress in internet gamblers (2019)

  34. Has gambling gatecrashed our teens? (2017)

  35. Shedding Light on Gambling Disorder as an Addiction: A Guide for Practitioners | Addiction Technology Transfer Center Network

  36. Shedding Light on Gambling Disorder as an Addiction: A Guide for Practitioners | Addiction Technology Transfer Center Network

  37. Gambling Harm as a Global Public Health Concern: A Mixed Method Investigation of Trends in Wales (2020)

  38. The epidemiology and impact of gambling disorder and other gambling-related harm (2017)

  39. The social cost of gambling to Victoria (2017)

The author, Dawn Teh, is a health writer and former psychologist who enjoys exploring topics about the mind, body, and what helps humans thrive.

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