Suicides among black kids have nearly doubled in the past 20 years, according to research published in JAMA Pediatrics, though the overall suicide rate was stable.

Researchers found that between 1993 and 2012, 657 black children between the ages of 5 and 11 killed themselves. It’s a significant increase, especially considering that suicide typically is less common among black youth than their white peers. Indeed, during the same time period, suicides for white children dropped.

The researchers couldn’t offer any reason for the increase in suicide, suggesting that more study will be needed. They believe the numbers indicate that it’s never too early to institute suicide-prevention techniques.

“Although rates of suicide in adolescents aged 12 to 19 years are roughly 50 times higher than suicide rates in children aged 5 to 11 years, investment in upstream suicide prevention approaches that occur prior to the onset of suicidal behavior may have strong potential to reduce suicide rates,” the scientists wrote in the study. (Time)