U of M researchers were investigating the compound, N-acetyl cysteine. They found it helps boost a natural neurochemical that is often out of balance in the brains of people with addictions. The neurochemical is called glutamate and it is associated with reward signals in the brain.
In the double-blind study, 83 percent of those who took the amino acid supplement NAC reported fewer urges to gamble.
"When people responded, which was the majority of people, they responded quite robustly," according to Dr. Jon Grant, the lead investigator on the study. "People were saying this was getting rid of their urges to gamble. They felt more in control of their gambling behavior."
In contrast, a control group was given an inactive supplement. Grant says most reported that their urges got worse and they went back to gambling.
"Only 29 percent of those on placebo were able to maintain any of their improvement that they had gotten previously. So this told us that there was some type of effect going on from this amino acid," Grant said.
But the extent of that effect is hard to pin down at this stage. Grant's study group was small. Only 13 people participated in the trial. Because of that, he was not able to prove that his findings are statistically significant. But Grant says his results show a great trend toward statistical significance on multiple measures.
Dr. John Krystal, editor-in-chief of "Biological Psychiatry," the journal that published Grant's article, says at the very least Grant has provided preliminary evidence for a connection between the glutamate system and pathological gambling.
"It's really an important and difficult step even to generate a positive finding in a pilot study like this. So it's important and very encouraging that Dr. Grant and his colleagues have provided some very encouraging data," said Krystal, who is a professor of psychiatry at Yale University.
Grant is currently seeking funding for a much larger study to verify his results. He says nationally the quest to find medications to treat gambling addictions is still very much in its infancy with most of the discoveries in the field only occurring within the past seven years.
In addition to Grant's preliminary amino acid findings, researchers have also had some success treating pathological gamblers with opiate antagonists - the same drugs that are often used to treat alcoholism. Anti-depressants also have been effective for some problem gamblers.
Grant says his work with the amino acid NAC is an attempt to provide yet another option.
"What all of these studies have sort of shown us over the years is that gambling may be a fairly heterogeneous disorder in terms of its underlying biology," he said. "So some people may respond to one type of medication, where other people with a gambling problem may respond to a different type of medication."
If Grant is able to prove that an amino acid is effective at treating gambling addictions, he says it would give patients a cheaper -- possibly safer -- alternative to pharmaceutical drugs. But until his findings are verified, he discourages people from experimenting with health food supplements for gambling addictions. Grant says there's not much oversight of supplements compared to pharmaceutical drugs. And he says its not clear whether it's safe to take NAC while pregnant or while taking other medications.