Advocates of medical marijuana often bring up the belief that it could help increase pain tolerance or provide relief to those suffering from some sort of chronic pain. New research, however, points to the exact opposite and suggests that pot smokers might actually become less tolerant to pain over time.

While the new study conducted by researchers at the Swedish Medical Center in Colorado, and published Tuesday in the journal, Patient Safety in Surgery, acknowledged that smoking marijuana can provide pain relief in the short term, the findings suggested that pot users reported being in greater pain after a traumatic injury than those who didn’t use the drug. Furthermore, the study noted that those who smoked marijuana also required higher doses of opioid painkillers than non-smokers did.

According to a report from Live Science, the study involved about 260 trauma patients from Colorado and Texas, all of whom were involved in vehicular accidents between January and April, 2016. Some of these patients regularly smoked marijuana and were found to have low pain tolerance and a greater need for narcotic painkillers. Live Science noted that there were four times as many marijuana users from the Colorado area than in Texas, as the drug is legal for both medicinal recreational purposes in the former state, and illegal for both in the latter.

Out of all the patients, about 21 percent said that they had recently smoked pot or tested positive for the drug, while 6 percent said that they consumed marijuana on a daily or near-daily basis. Nine percent of the patients tested positive for other “street” drugs or prescription drugs, including, but not limited to amphetamines, methamphetamine, cocaine, and opiates.

All in all, patients who consumed marijuana, but didn’t take any other drugs, were found to consume an average of 7.6 milligrams of opioid painkillers a day, or close to 25 percent more than the 5.6 milligrams consumed by patients who were drug-free. Additionally, the study found that the marijuana users had worse pain tolerance, as they gave their pain an average rating of 4.9 out of 10, as compared to non-marijuana users, whose daily pain score was only 4.2.

BREAKING: Marijuana will be legal in Canada starting October 17. Canada is the second country to legalize marijuana, after Uruguay. pic.twitter.com/4hixjmolUX — AJ+ (@ajplus) June 20, 2018

At the moment, the results of the study are still preliminary, as the researchers only looked at a small number of patients and still require more research to confirm their findings. However, Live Science wrote that the research provides new insight into the effects of marijuana on pain tolerance, given how more and more people appear to be consuming the drug as more locations legalize it for medicinal and/or recreational purposes.

Speaking to Live Science, UCHealth Burn Center medical director Dr. Anne Wagner said that she agrees with the results of the study, as her separate research on burn patients likewise showed that heavy pot smokers required “much higher doses” of opioids to relieve their pain.

“I really think a lot of people think [marijuana is] very harmless. I don’t think they’re at all aware about … how much it’s going to affect them in their recovery,” said Wagner, who was not involved in the Swedish Medical Center study.