From Impulsivity to Addiction: Gambling Disorder and Beyond

One of the many interesting shifts in DSM-5 was the reclassification of pathological gambling from the impulse control disorders category to substance addictions (“substance-related and addictive disorders”). The shift effectively recognized (the now re-labeled) “gambling disorder” as the first behavioral addiction. This is a fascinating construct in psychiatry. The other diagnoses in this category involve the compulsive administration of exogenous drugs. Much of our knowledge of addiction comes from studying the pharmacology of these drugs and their ability to “hijack” reward-oriented behavior in animal models.

[[{"type":"media","view_mode":"media_crop","fid":"40387","attributes":{"alt":"© katalinks/shutterstock.com, gambling","class":"media-image media-image-right","id":"media_crop_4132918533744","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4131","media_crop_rotate":"0","media_crop_scale_h":"200","media_crop_scale_w":"130","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"© katalinks/shutterstock.com","typeof":"foaf:Image"}}]]In the case of gambling disorder, there is no exogenous substance; rather, there is excessive engagement in a behavior in which money is wagered on the uncertain prospect of a larger monetary prize. Even the role of money is unclear in this equation. While money is self-evidently a potent incentive, at a psychological level, it is a complex, learned reinforcer (as distinct from a natural reward, such as food or sex). For at least some gamblers, winning money appears to play a negligible role in maintaining their behavior.¹

So what is it about this behavior that enables gambling to yield a power that is comparable to drugs such as cocaine, heroin, and alcohol? And might other behaviors, such as video gaming, food addictions, shopping, and sex, be conceptualized as addictive behaviors in the future?

Recognizing the disordered gambler

The DSM-5 diagnosis of gambling disorder uses a threshold of 4 of 9 symptoms. These symptoms have changed little from the original list in DSM-III, which was based on the diagnostic criteria for substance dependence. The symptoms include classic hallmarks of an addiction syndrome: preoccupation with gambling, gambling with larger amounts over time (akin to tolerance), and agitation when stopping gambling (akin to withdrawal).

The criteria also emphasize the negative consequences of gambling, such as occupational or interpersonal difficulties, borrowing money, and lying about gambling. Certainly, financial debt is ubiquitous in individuals with gambling disorder, and in the rare cases that do not involve significant debts, there is usually either some form of bailout from others or bankruptcy.

Gambling disorder is linked to high rates of criminal acts to support gambling, although clinicians should note that criminality was dropped as a specific criterion in DSM-5. Homelessness, physical health burden, and suicidal behavior are further corollaries that highlight the ultimately catastrophic downward spiral of gambling disorder.

Another feature that does not have an obvious counterpart in drug addiction is loss-chasing: continuing to play or returning to the venue at a later date in an effort to claw back recent debts. Loss-chasing is often regarded as a tipping point at which recreational gambling becomes problematic. In epidemiological datasets, loss-chasing is generally the most endorsed feature.² These population studies also illustrate how the harms of gambling are continuously distributed: individuals who do not meet diagnostic criteria can nonetheless experience clear harm from gambling. The prevalence estimates for “at risk” gambling are in the range of 2% to 7%, with full DSM diagnosis in 0.5% to 1%.³

Neurobiological correlates

One of the pivotal lines of evidence that shaped the DSM-5 reclassification was the neurobiological overlap between gambling disorder and the substance use disorders. From a neurocognitive perspective, elevated impulsivity is a reliable feature in patients with gambling disorder.⁴ This personality trait refers to the tendency for rapid responses and unplanned decisions. It can be measured with either questionnaires or behavioral tasks, and is conceptualized as arising from an imbalance between overactive subcortical reward systems and underactive prefrontal cortical control mechanisms.⁵ Similar cognitive markers are apparent in substance use disorders.⁴ Impulsivity tends to predate gambling disorder as well as other addictions, with predictive value from early childhood.⁶

Neuroimaging experiments have begun to characterize the underlying neural basis of gambling disorder. Functional MRI studies illustrate changes in brain reward circuitry, centered on the ventral striatum and medial prefrontal cortex.⁷ This system is robustly activated in healthy volunteers by winning money and during risky gambling decisions.⁸ While these areas are abnormally recruited in persons with gambling disorder (and also in drug addicts), the precise nature of this pathophysiology is proving elusive, with reports of hypoactivity and hyperactivity in equal measure.⁷

Positron emission tomography studies may help untangle these complex findings, by identifying the neurochemical modulators within this circuitry, which may also guide medication development. In persons with substance use disorders, there is a reduction in dopamine D2 receptors in the striatum; problem gamblers show a similar effect, albeit only in those with higher levels of trait impulsivity.⁹ Persons who have gambling disorder also show heightened levels of dopamine release.¹⁰ This finding is consistent with a clinical observation that dopamine agonist treatments for Parkinson disease can sometimes induce excessive gambling and other risky reward behaviors.¹¹

Video games and Internet use

DSM-5 changes to the addictions category “Internet gaming disorder” were also considered, but the scientific research behind this condition was insufficient. Ultimately, it was listed in section III of DSM-5 as a condition for further study. This has triggered a wave of research on the clinical, epidemiological, and neurobiological aspects of excessive video gaming. Prevalence rates are particularly alarming in youths: a US survey of 8- to 18-year-olds reported pathological video gaming in 8%.¹² A recent study in 12,000 teenagers across 11 European countries found problematic Internet use in 4.4%.¹³

We are now seeing progress in refining the clinical phenotype. It is recognized that the Internet is a route of access to a range of different activities (also including gambling and pornography). There is international consensus on 9 diagnostic criteria for Internet gaming disorder.¹⁴ The threshold of 5 of 9 symptoms is slightly higher than for gambling and substance addictions.

At a psychological level, video games have much in common with gambling (eg, their unpredictable schedules of reinforcement and their capacity to provide distraction from or a means of coping with life stresses). Although there is emerging neurobiological overlap with gambling disorder and substance use disorders, in terms of cue-induced cravings and impulsivity, challenges remain.¹⁵

One concern is the gradual pathologization of everyday behaviors. The negative consequences of gambling disorder are irrefutable, primarily with respect to the debts arising from excessive gambling. For excessive gaming (and many other “soft” addictions), the negative consequences can be much harder to quantify and relate to time expenditure, a loss of productivity (eg, as a consequence of late nights), or failure to prioritize real-life responsibilities (eg, education, child care).

Food addiction

Obesity is a third area that has seen a recent emergence of credible research within a framework of behavioral addiction. Scientists recognize that obesity is a heterogeneous health problem with multiple determinants. A detailed understanding of the neuroscience of feeding behavior has laid the foundation for the concept of “food addiction” as a potentially useful description of at least a subtype of obese persons.

Persons with food addiction can potentially benefit from the translation of existing effective treatments for drug addiction, such as medications that target µ-opioid receptors.¹⁶ Food cues recruit the same neuroanatomical and neurochemical systems that are targeted in drug addiction. Exogenous stimulation of these neural hot spots can trigger excessive and binge-like eating beyond satiety.¹⁷ Indeed, binge eating disorder has emerged as the phenotype, with the greater clinical and neurobiological resemblance to an addiction profile. In one study, dopamine release to food cues was enhanced in binge eaters but not in non–binge eaters.¹⁸ This is comparable to the aforementioned effect in problem gamblers.

Preclinical models of sugar-bingeing rodents showed progres-sive behavioral signs of dependence as well as a range of neuroadaptive changes in the brain that were previously thought to be confined to drugs of abuse.¹⁹ Some of these effects were also seen in experimental models looking at binge-like administration of fatty foods.

As with electronic forms of gambling and video games, we must bear in mind that modern food stuffs are highly engineered products, and certain sugar-fat combinations can have powerfully rewarding properties. An ongoing dispute is whether this putative syndrome is best described in relation to the behavior (eating addiction) or a particular dietary substance (food addiction).²⁰

Treatment implications

The DSM-5 reclassification has raised the profile of gambling disorder, which appears to be having a beneficial effect on treatment. Nevertheless, services that are available for disordered gambling, and their degree of integration with other mental health services, vary widely across jurisdictions. This is particularly pronounced in the US, given that state-specific gambling regulation entails state-specific treatment provision for those with problematic gambling.

In general, first-line treatment is cognitive-behavioral therapy (CBT), which aims to identify gambling triggers and provide alternative means of coping with those triggers. In addition, CBT seeks to identify and restructure any faulty cognitive distortions about gambling, such as the tendency to over-interpret winning or losing streaks in play or the significance of gambling near-misses.

The human brain is naturally limited in its grasp of randomness and chance and its ability to reason about low-likelihood events (such as lottery wins); these faulty cognitions are more evident in individuals with gambling disorder. A recent Cochrane review of psychological treatments for gambling disorder concluded that CBT has moderate efficacy²¹; it is also adaptable to group settings and Web-based modes of delivery.

As with other addictions, only a minority of affected individuals actively seek treatment for gambling disorder. Most jurisdictions offer additional forms of support that include telephone helplines and voluntary self-exclusion programs in which the gambler can request that gambling venues or Web sites refuse him or her future entry or credit.

CBT is also frequently augmented with financial counseling and family therapy. With few large-scale randomized controlled trials, there is no clear evidence for the effectiveness of pharmacological treatments for gambling disorder. There are promising signs of efficacy for opioid receptor antagonists, although the mechanism of action is unclear, and SSRIs and mood stabilizers may be beneficial in individuals with depressive or bipolar comorbidities.²²

Conclusions

Behavioral addictions are a nascent construct in psychiatry, and they have been ratified in principle by the inclusion of gambling disorder in the DSM-5 addictions category. Given the lack of accepted biomarkers for addictions, it remains to be seen which conditions will join gambling disorder.

From a clinical perspective, gambling disorder is a debilitating condition that is frequently comorbid with other mental health problems-including substance use, mood, and anxiety disorders. Gambling represents a potent means of regulating negative mood states (via distraction or the prospect of an exciting win), but one that confers the inevitability of long-term losses. As such, a diagnosis of gambling disorder is likely to exacerbate comorbid conditions and is highly relevant to their treatment. It is recommended that clinicians across all mental health services screen patients for gambling disorder.

Disclosures:

Dr Clark is Director of the Centre for Gambling Research at UBC in the department of psychology at the University of British Columbia in Vancouver. The Centre for Gambling Research at UBC is supported by funding from the Province of British Columbia and the British Columbia Lottery Corporation. He receives research funding in the UK from the Medical Research Council, and he is a paid consult to Cambridge Cognition Ltd on issues relating to neurocognitive assessment. Dr Clark has not received any direct or indirect payments from the gambling industry or any other groups substantially funded by gambling to conduct research or to speak at conferences or events.

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