“The reclassification of gambling disorder in the DSM-5 was not a political decision. It was a scientific one,” says Dr. Ponlawat Pitsuwan, Physician and Addiction Medicine Specialist at Phuket Island Rehab. “When we scan the brain of someone with severe gambling disorder and compare it to the brain of someone with cocaine dependence, the patterns of reward-system dysfunction are remarkably similar. The substance is different, but the neurobiology of compulsion is the same.”
The Neuroscience: Why Gambling Hijacks the Brain
Gambling exploits the dopamine reward system more efficiently than almost any other non-pharmacological stimulus. The key mechanism is the variable ratio reinforcement schedule, the same principle that underlies slot machine design, sports betting, and poker: rewards are delivered at unpredictable intervals, maximising the reward prediction error signal that drives dopamine firing in the ventral tegmental area (VTA) and nucleus accumbens.
What makes gambling uniquely compelling is the role of near-misses. Neuroimaging research has shown that near-miss outcomes (the slot machine showing two matching symbols with the third just off) activate the reward circuitry almost as strongly as actual wins. The brain processes the near-miss as evidence that a win is close, maintaining engagement and motivation to continue despite the mathematical reality that near-misses are losses. This near-miss effect is more pronounced in problem gamblers than in recreational gamblers, suggesting that vulnerability to gambling disorder may involve an exaggerated reward prediction error response.
Cognitive distortions play a central role. The gambler’s fallacy (believing that past outcomes influence future probabilities in independent events), illusory control (believing that skill or ritual can influence random outcomes), and selective memory (remembering wins more vividly than losses) are cognitive biases that maintain gambling behaviour. These distortions are mediated by the prefrontal cortex, the same brain region impaired in substance use disorders, and they respond to the same cognitive behavioural therapy interventions.
| Neurobiological Feature | Gambling Disorder | Substance Use Disorder |
|---|---|---|
| Ventral striatum reactivity to cues | Increased activation to gambling cues and near-misses | Increased activation to drug cues |
| D2 receptor availability | Reduced in the striatum | Reduced in the striatum |
| Prefrontal cortical function | Impaired impulse control and decision-making | Impaired impulse control and decision-making |
| Genetic overlap | Shared genetic vulnerability with AUD (twin studies) | Polygenic, partially overlapping with gambling risk genes |
| Tolerance | Needing to bet larger amounts for the same excitement | Needing larger doses for the same effect |
| Withdrawal | Restlessness, irritability when attempting to stop | Physical and psychological symptoms |
Online Gambling and the Acceleration of Disorder
The migration of gambling to online platforms has dramatically lowered barriers to problematic use. Physical casinos impose natural friction: travel time, operating hours, the social visibility of gambling, and the physical act of handing over cash. Online gambling eliminates all of these: 24-hour access, private use, digital transactions that obscure the reality of spending, in-play betting that allows continuous wagering during live sporting events, and algorithmic personalisation of promotional offers targeting vulnerable users.
Mobile gambling apps are particularly concerning because they create a pattern of intermittent checking and micro-betting throughout the day, similar to the compulsive phone-checking behaviour seen in problematic social media use. The integration of gambling features into video games (loot boxes, virtual casinos within games) further blurs the boundary between gaming and gambling, particularly for younger users whose prefrontal cortical development is incomplete.
Co-Occurrence with Substance Use Disorders
Gambling disorder has one of the highest rates of co-occurrence with substance use disorders of any psychiatric condition. Research consistently shows that approximately 40 to 60 per cent of individuals with gambling disorder also meet criteria for a substance use disorder, most commonly alcohol use disorder. The shared vulnerability is neurobiological: lower baseline D2 receptor availability, impaired prefrontal cortical function, and heightened stress-system reactivity predispose individuals to both conditions simultaneously.
At Phuket Island Rehab, patients presenting with substance use disorders are screened for co-occurring gambling disorder because treating one without identifying the other leads to poor outcomes. The treatment approach for gambling disorder uses the same evidence-based modalities as substance addiction treatment: CBT targeting cognitive distortions and urge management, mindfulness-based relapse prevention, and structured aftercare with financial counselling and self-exclusion strategies.
When Substance Use Has Become More Than Occasional
If gambling and substance use are both present, they almost certainly share the same underlying reward-system vulnerability. Alcohol lowers inhibitions, increasing risky betting. Stimulants enhance the sense of invincibility and risk tolerance. The financial stress of gambling losses drives anxiety and depression, which in turn drives more substance use for emotional regulation. This interlocking cycle accelerates both conditions and requires integrated treatment that addresses both simultaneously.
Summary
Gambling addiction is a recognised mental illness, classified alongside substance use disorders in the DSM-5 based on shared neurobiology. The dopamine reward system, prefrontal cortical function, and genetic vulnerability overlap substantially with substance addiction. Variable ratio reinforcement and near-miss effects make gambling uniquely effective at exploiting the reward prediction error system. Online and mobile gambling have accelerated disorder onset by removing natural friction. Co-occurrence with substance use disorders is high (40 to 60 per cent), and integrated treatment addressing both conditions produces the best outcomes.
“When the DSM-5 moved gambling disorder into the addictions chapter, it validated what clinicians had been observing for decades,” says Dr. Ponlawat Pitsuwan. “The patient who cannot stop gambling despite losing their home is experiencing the same loss of voluntary control as the patient who cannot stop drinking despite losing their liver. The object of the compulsion is different, but the brain’s inability to override the drive is identical. And thankfully, the treatments that work for one work for the other.”
Frequently Asked Questions
Is gambling addiction officially classified as a mental illness?
Yes. The DSM-5 (2013) reclassified gambling disorder from the impulse-control disorders chapter to the Substance-Related and Addictive Disorders chapter, placing it alongside alcohol and drug use disorders. This reclassification was based on extensive evidence of shared neurobiology, genetics, and treatment response with substance addictions.
What causes gambling addiction?
Gambling disorder results from the interaction of neurobiological vulnerability (reduced D2 receptor availability, impaired prefrontal function), genetic predisposition (heritability estimated at 50 to 60 per cent from twin studies), environmental factors (early exposure, availability, advertising), and the reinforcement properties of gambling itself (variable ratio reinforcement, near-miss effects, cognitive distortions).
Can gambling addiction be treated like drug addiction?
Yes. The evidence-based treatments for gambling disorder are the same as those for substance use disorders: CBT (targeting cognitive distortions and urge management), motivational interviewing, mindfulness-based relapse prevention, and, in some cases, pharmacotherapy (naltrexone has shown efficacy in reducing gambling urges by modulating the opioid-mediated reward response).
How common is gambling addiction?
Prevalence estimates range from 0.5 to 3 per cent of the adult population for gambling disorder, with an additional 2 to 5 per cent classified as problem gamblers (experiencing harm but not meeting full diagnostic criteria). Rates are higher among young men, individuals with co-occurring substance use or mood disorders, and populations with high gambling availability.
Is online gambling more addictive than casino gambling?
Online gambling removes natural friction points (travel, operating hours, physical cash transactions) and introduces features that accelerate problematic use: 24-hour access, in-play betting, digital transactions, algorithmic targeting of promotions, and the privacy that enables concealment. Research suggests that online gamblers develop problems faster than those who gamble exclusively in physical venues.
Can you be addicted to both gambling and alcohol?
Yes, and this is extremely common. Approximately 40 to 60 per cent of individuals with gambling disorder also have a co-occurring substance use disorder, most frequently alcohol. The shared neurobiological vulnerability (D2 receptor system, prefrontal cortical function) predisposes individuals to both conditions. Alcohol also disinhibits decision-making, increasing risky betting behaviour.
Related Reading
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Sources
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). 2013.
Clark, L. et al. “Pathological Choice: The Neuroscience of Gambling and Gambling Addiction.” Journal of Neuroscience, 2013.
National Council on Problem Gambling. ncpgambling.org
Gambling addiction · gambling disorder · DSM-5 behavioural addiction · variable ratio reinforcement · near-miss effect · reward prediction error · ventral striatum · D2 receptor · prefrontal cortex · gambler’s fallacy · illusory control · cognitive distortion · online gambling · in-play betting · loot boxes · naltrexone · co-occurring substance use disorder · alcohol and gambling · impulse control · twin studies heritability