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Visions Journal

A reminder that this article from our magazine Visions was published more than 1 year ago. It is here for reference only. Some information in it may no longer be current. It also represents the point of the view of the author only. See the author box at the bottom of the article for more about the contributor.

Slot machines, gambling disorder and responding to behavioural addiction

Luke Clark, PhD

Reprinted from the "Problem Gambling and Video Gaming" issue of Visions Journal, 2018, 14 (2), p. 27

Gambling originated in human societies thousands of years ago. The determination of a prize on the throw of a dice or the spin of a wheel taps into our basic fascination with chance, fate, hope and luck. Modern, commercial forms of gambling, including lotteries and casino slot machines, are designed with what is called a “house edge”—a negative expected value (in economic terms), which makes these games profitable for gambling operators and governments.

The flipside of this design is the inevitable financial loss sustained over time by gamblers. The harms associated with gambling arise from these losses. One of the hallmark features of problem gambling is “loss chasing,” or repeated gambling in an effort to recoup earlier losses. Loss and debt also fuel the negative consequences of gambling: a gambler might lie about money, borrow money or argue with family and friends about money.

The first behavioural addiction

As a medical illness, gambling disorder was first recognized in 1980 and termed “pathological gambling” in the third edition of the Diagnostic and Statistical Manual of Mental Disorders by the American Psychiatric Association (DSM-3). In 2013, a surge of research from psychology and neuroscience led to the DSM-5 re-positioning the condition—now called gambling disorder—alongside the substance addictions.1 Gambling disorder thus became the first behavioural addiction.

Recent decades have seen a gradual increase in the number and type of gambling opportunities, but this increase in opportunity is offset by an increased awareness among the general population of gambling harms and increased attention on treatment and prevention. Strategies to mitigate gambling harms are sometimes collectively termed “responsible gambling.”

Like many jurisdictions, British Columbia undertakes regular surveys to assess the prevalence of gambling problems among its residents. In a 2014 BC survey, 3.3% of the sample (3,058 adults) met the threshold for problem gambling, with 0.7% meeting the criteria to be diagnosed with gambling disorder.2 Men, younger adults and lower-income individuals were more likely to report problem gambling behaviours. The results of this survey mirror observations in many other parts of the world. These rates appear to be stable over time, and slight fluctuations from one survey to the next may be explained by subtle changes in the survey design.

The brain basis of gambling cravings

The reclassification of gambling disorder as a behavioural addiction was prompted by several lines of evidence. Some of the research in my lab at the University of British Columbia’s Centre for Gambling Research has examined personality traits (including impulsivity and decision-making biases) as well as brain changes (such as those in the dopamine system) in people with gambling problems.3 Personality traits and brain changes are associated with the development of gambling disorder as well as with the development of substance addictions.

In a recent experiment,4 we studied the brain basis of cravings in men with gambling problems. We used a technique called “cue reactivity,” where the participant views photos associated with gambling during a brain scan. We also tested a healthy group of non-gambling men. All participants saw some neutral photos as well as the gambling photos. The group with gambling problems showed heightened reactivity to the gambling images in the brain’s frontal cortex, the striatum and the insula. These areas of the brain are also frequently observed during similar tests in research on substance addictions.

In our experiment, we found that activity in the insula was directly related to how much each gambler craved while they viewed the gambling photos. This suggests that the insula may be especially important in generating the urge to gamble. The effects of visual gambling images on the brain are very relevant to the treatment and prevention of problem gambling behaviours. For example, gambling advertisements often contain such cues and can often trigger cravings and relapse in people with gambling problems.5

Different forms of gambling

In my lab, we have been paying increasing attention to the differences between different forms of gambling. We regard modern slot machines as one of the most harmful forms of gambling.6 For the people we see in Vancouver with gambling problems, slot machines are by far the most common preferred form of gambling.

When the Centre for Gambling Research was launched in 2014 at UBC, the BC Lottery Corporation donated a number of authentic slot machines to aid our research. These are housed in our Casino Lab. Much of our investigation has considered single features of slot machines (such as “near miss” events, where the gambler appears to narrowly miss a big payout) to understand how people become addicted to these games.

Recently, we have also looked at the psychological processes that underlie “immersion” in slot machine play, where players enter a trance-like state. Immersion seems to be more closely linked to slot machines than other forms of gambling, and it is also associated with problem gambling.7 Ultimately, however, as these games contain many psychological features, it is unlikely that one specific element will fully explain the addictive capacity of slot machines.

What we can do about problem gambling

For BC residents who feel their gambling might be getting out of control (and for family members of gamblers), there are a number of supports available, including a telephone helpline and a dedicated treatment service offered by the BC Responsible & Problem Gambling Program ( There is also a self-exclusion program that enables a gambler to ban themselves from casino venues across the province.

The main shortcoming with these programs is that they are currently used by only a minority of the people with gambling disorder. Stigma may be a contributing factor: gamblers may feel hesitant to use the systems because of the shame or criticism they experience as an individual with a gambling problem. There is some evidence that problem gambling is associated with even greater levels of stigma than substance addictions.8

We also need to do much more to prevent the development of gambling problems in the first place. One of the objectives of our research on slot machine immersion is ultimately to encourage the modification of these games to reduce their capacity to immerse players for extended periods. This kind of modification could include pop-up messages that encourage the user to take a break from the game, or display their cumulative spending levels.

Finally, the gambling landscape has been transformed by recent developments in technology, creating new opportunities to gamble in the home or on mobile devices (via online gambling), as well as increasing the exposure of youth to new gambling options, such as free games on social media platforms.9 In order for our communities to anticipate and respond to these developments, a close dialogue is needed between gambling operators, regulators and academic researchers. Ultimately, the recognition of gambling as a public health issue must pave the way for the funding of gambling services (treatment, prevention, education), akin to current public health approaches to substance use and substance addictions.

About the author

Dr. Clark is Director of the Centre for Gambling Research at UBC and an associate professor in UBC’s Department of Psychology. The centre was launched in 2014 with joint funding from the Province of BC and the British Columbia Lottery Corporation. Find the centre at and Dr. Clark on Twitter at @LukeClark01 and @CGR_UBC

  1. Petry, N.M., Zajac, K. & Ginley, M.K. (2018). Behavioral addictions as mental disorders: To be or not to be? Annual Review of Clinical Psychology, 14, 399-423.

  2. See

  3. Clark, L. (2014). Disordered gambling: The evolving concept of behavioral addiction. Annals of the New York Academy of Sciences, 1327(1), 46-61.

  4. Limbrick-Oldfield, E.H., Mick, I., Cocks, R.E., McGonigle, J. Sharman, S.P., Goldstone, A.P., Stokes, P.R.A., Waldman, P., Erritzoe D., Bowden-Jones, H., Nutt, D., Lingford-Hughes, A. & Clark, L. (2017). Neural substrates of cue reactivity and craving in gambling disorder. Translational Psychiatry, 7, e992. doi:10.1038/tp.2016.256.

  5. Hanss, D., Mentzoni, R., Griffiths, M.D. & Pallesen, S. (2015). The impact of gambling advertising: Problem gamblers report stronger impacts on involvement, knowledge, and awareness than recreational gamblers. Psychology of Addictive Behaviors, 29(2), 483-491. doi: 10.1037/adb0000062. 

  6. Murch, W.S. & Clark, L. (2016). Games in the brain: Neural substrates of gambling addiction. The Neuroscientist, 22(5), 534-545. doi: 10.1177/1073858415591474.

  7. Murch, W.S., Chu, S.W.M. & Clark, L. (2017). Measuring the slot machine zone with attentional dual tasks and respiratory sinus arrhythmia. Psychology of Addictive Behaviors, 31(3), 375-384.

  8. Konkolÿ-Thege, B., Colman, I. & Hodgins, D.C. (2015). Social judgments of behavioral versus substance-related addictions: A population-based study. Addictive Behaviors, 42, 24-31.

  9. Kim, H.S., Wohl, M.J., Salmon, M.M., Gupta, R. & Derevensky, J. (2015). Do social casino gamers migrate to online gambling? An assessment of migration rate and potential predictors. Journal of Gambling Studies, 31(4), 1819-1831. doi: 10.1007/s10899-014-9511-0.

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