Whereas some people are strong, others are weak. But some of that innate toughness might be due simply to a greater inherited tolerance for pain — a matter of perception. In a new study, researchers from Proove Biosciences say they’ve now identified the genes responsible for that variance in pain tolerance.

"Our study is quite significant because it provides an objective way to understand pain and why different individuals have different pain tolerance levels," study leader Tobore Onojjighofia said in a press release. "Identifying whether a person has these four genes could help doctors better understand a patient's perception of pain."

The research team examined the genetics of more than 2,700 diagnosed with chronic pain, looking for a gang of genetic suspects: COMT, DRD2, DRD1 and OPRK1. The study participants, all of whom were taking prescription opioids for pain, rated their perception of pain on a scale of zero to 10. Nine percent of the study group reported experiencing a low perception of pain, while 46 percent experienced moderate, and another 45 percent complained of suffering a high perception of pain. Those who reported no pain were thrown out of the study.

In the analysis, Onojjighofia and his colleagues found a greater prevalence of the DRD1 gene variant among those who reported low pain perception, seen 33 percent more than otherwise. Likewise, the COMT and OPRK variants were found 25 percent and 19 percent more often among those with moderate pain compared to those with high pain. And the DRD2 variant appeared 25 percent more often among those with the highest pain perception compared to those with moderate pain.

Onojjighofia presented the findings to the American Academy of Neurology’s annual meeting on Sunday. "Chronic pain can affect every other part of life," Onojjighofia said in the release. "Finding genes that may be play a role in pain perception could provide a target for developing new therapies and help physicians better understand their patients' perceptions of pain."

Chronic pain is the perception of pain persisting for longer than three to six months, depending upon one’s definition. Such pain beyond the normal process of healing becomes a condition in itself, affecting 100 million Americans and 1.5 billion people around the world, according to the American Academy of Pain Medicine.