New research shows that the natural opioid system in the brains of pathological gamblers responds differently, which may help explain why gambling can become an addiction.
A group of UK researchers note that gambling is widespread, with about 70 percent of the British population gambling occasionally. However, for about 0.6 percent of British adults — or about 300,000 people — gambling has spiraled out of control, taking on the features of an addiction.
For their study, which was presented at the European College of Neuropsychopharmacology Congress in Berlin, researchers recruited 14 pathological gamblers and 15 healthy volunteers, and used Positron Emission Tomography (PET) scans to measure opioid receptor levels in their brains.
These receptors allow cell to cell communication — they are like a lock, with the neurotransmitter or a chemical, such as endogenous opioids called endorphins, acting like a key, the researchers explain.
The researchers found no differences between the receptor levels in pathological gamblers and non-gamblers. This is different than in people addicted to alcohol, heroin or cocaine, where increases are seen in opioid receptor levels, according to the researchers.
All the volunteers were then given an amphetamine tablet that releases endorphins, which are natural opiates, and the PET scan was repeated. The scan showed that the pathological gamblers released less endorphins than non-gambling volunteers, the researchers report. The gamblers also reported less euphoria from the endorphin rush than the healthy volunteers.
“From our work, we can say two things,” said lead researcher Dr. Inge Mick. “Firstly, the brains of pathological gamblers respond differently to this stimulation than the brains of healthy volunteers. And secondly, it seems that pathological gamblers just don’t get the same feeling of euphoria as do healthy volunteers. This may go some way to explaining why the gambling becomes an addiction.”
The researcher noted that this is the first PET imaging study to look at the involvement of the opioid system in pathological gambling, which is a behavioral addiction.
“Looking at previous work on other addictions, such as alcoholism, we anticipated that pathological gamblers would have increased opiate receptors, which we did not find, but we did find the expected blunted change in endogenous opioids from an amphetamine challenge,” she said.
“These findings suggest the involvement of the opioid system in pathological gambling and that it may differ from addiction to substances such as alcohol. We hope that in the long run this can help us to develop new approaches to treat pathological gambling.”