Even as much of the country deals with an opioid addiction epidemic from a possible over-prescription of pain killers, some Americans are unable to get their hands on pain medication they need.

Many facing these difficulties are racial minorities and people of color, especially black and Hispanic Americans, according to the New York Times. Research shows blacks are 34 percent less likely than whites to be prescribed opioid pills for pain. There is evidence that racial biases plays a role in such disparities.

One researcher, Adam Hirsch, suggested a few possible explanations. Some doctors might believe black people might be more likely to abuse or become addicted to the drugs and so don’t prescribe them. Or some doctors feel subconsciously less sympathetic toward the pain of patients who don’t look like them (which could be a problem for white doctors treating black patients) and so don’t prescribe as strong of pain killers.

Check out the New York Times to see the breakdown of what is actually racial bias in pain treatment, what could be attributed to class, money or insurance, and how some studies are aiming to find new ways to manage pain.