Brain imaging provides insight into the biological roots of gambling addiction

A new doctoral dissertation from the University of Turku shows that gambling disorder is rooted in specific brain networks responsible for reward and self-control. The research indicates that people with this condition have measurable changes in how their brain regions communicate and process information. These findings suggest that the struggle to stop gambling is tied to biological shifts in the brain rather than a simple lack of willpower.

Gambling disorder is currently recognized as the only behavioral addiction in major medical manuals. This classification reflects the many ways that problem gambling resembles addiction to alcohol or drugs.

Albert Bellmunt Gil, a researcher at the University of Turku, led this work to better understand the internal mechanics of the condition. Many researchers focus on a specific circuit that connects the front of the brain to deeper centers for reward and information filtering. This pathway acts as a bridge between the parts of the brain that seek rewards and the parts that manage behavior.

Most existing studies on this topic only look at one type of brain scan at a time. This approach provides a limited view of how the brain works. Bellmunt Gil sought to provide a more complete picture by using several different types of imaging technology at once. He also focused on different age groups to see how the condition might change over time. Many earlier studies focused only on young adults, which may miss changes that develop later in life.

The first part of the research involved a group of 15 people with gambling disorder and 17 healthy individuals. The team used functional magnetic resonance imaging to watch the brain in action. They also used positron emission tomography, which involves tracking special tracers to see how chemicals move in the brain. This allowed the team to look at three important chemical systems: dopamine, serotonin, and opioids.

When the researchers looked at the brain at rest, they found a change in how the reward center talks to the control center. In healthy people, there is a negative relationship between the nucleus accumbens and the dorsolateral prefrontal cortex. This means that as activity in one area goes up, it tends to go down in the other. In the group with gambling disorder, this relationship was lost.

The two areas did not balance each other in the same way. The team found that this change in communication was linked to serotonin levels. Serotonin is a chemical often associated with mood and the ability to resist impulses. The findings suggested that the way serotonin works in the reward center might influence how well a person can control their actions.

This specific connection was not related to dopamine or opioids during the resting state scans. The researchers also showed the participants videos of gambling, such as people playing poker or roulette. They compared the brain’s reaction to these clips with its reaction to neutral videos of people walking or doing everyday tasks. The people with gambling disorder showed a much stronger response in a region called the dorsal striatum when they saw gambling cues.

This area of the brain is often involved in forming habits. The heightened response to gambling cues was tied to the opioid system. Opioids in the brain help us feel pleasure and can influence how much we want something. The results indicated that the more active the opioid system was, the stronger the brain reacted to gambling triggers.

This finding mirrors what is often seen in people who are addicted to substances. However, the researchers did not find evidence of dopamine involvement in these specific tests. This result is notable because dopamine is usually seen as the primary chemical in drug addiction. In those cases, dopamine function is usually lower than normal, but in gambling disorder, the dopamine system seems to remain active or even hyperactive.

The second part of the study focused on 20 older adults with gambling disorder and 40 healthy controls. The participants in this group had an average age of 64 years. Using structural scans, the researchers measured the thickness and volume of different brain parts. They found that the older adults with the disorder had less gray matter in the orbitofrontal cortex and the thalamus.

These areas are essential for making decisions and filtering information. The team also examined the white matter, which acts like the wiring of the brain. The study found that the group with gambling disorder had less integrity in the white matter of the left anterior corona radiata. This area connects the frontal lobe to other parts of the brain.

The researchers also found more tiny lesions or damaged spots in this same region. These structural issues were linked to the severity of the person’s gambling problems. The presence of these lesions suggests that the physical health of the brain’s wiring plays a role in how well a person can resist the urge to gamble. This was the first study to report such findings regarding white matter lesions in this population.

The researchers note that their findings come from a relatively small number of participants. Small groups can sometimes make it harder to see the full range of differences between people. The results regarding some chemical tracers were not statistically significant in every test. This suggests that some aspects of the disorder might be more subtle or vary between individuals.

The study also looked at participants at a single point in time. This means it is not yet clear if the brain changes happened before the gambling started or if they were caused by years of gambling. Longitudinal studies following people over many years would help understand whether these brain abnormalities are a cause or a consequence of the behavior. Future work should also consider how other health factors might influence these brain structures.

Some researchers hope to use these findings to test new therapies like brain stimulation. By targeting the specific areas identified in this work, doctors might one day be able to help patients regain control over their habits. Medications that target serotonin or opioids might also be a path forward. Randomized controlled studies are needed to see if these medical interventions are effective for a broad range of patients.

Understanding these brain mechanisms can help reduce the stigma often associated with gambling problems. If the disorder is linked to measurable changes in the brain, it can be treated as a medical condition. This view may lead to more compassionate and effective ways to help those struggling with the habit. Improved prevention strategies could also be developed by identifying people who have similar brain patterns before a disorder develops.

The study, “Neurobiological correlates of gambling disorder: A multimodal brain imaging approach,” was authored by Albert Bellmunt Gil.