A new study is shedding light on how the bacterial composition in saliva can show a person’s risk for suicide.

The study by University of Florida researchers published in the journal Nature found a curious discovery in the saliva of college students who reported having recent thoughts of suicide.

The team tried to study suicidal ideation in the students by comparing their salivary bacterial profiles. They analyzed saliva samples from nearly 500 students and compared the results of students with recent suicidal thoughts with those who did not have thoughts about suicide.

While there may have been a growing body of research on mental health and its relation to the human biome, this was the first time scientists looked at bacterial data in the saliva of people with suicidal thoughts.

For the sake of the study, recent suicidal ideation was defined as thoughts of suicide within two weeks before the saliva sample was taken for examination.

The researchers found that students with recent suicidal ideation had higher levels of periodontal disease-causing bacteria and other bacteria associated with inflammatory health conditions.

The team notably found that the same students had lower levels of Alloprevotella rava, known to promote brain health. They also found a genetic variation in the students that may have influenced the presence of A. rava in their mouths.

According to first author Angelica Ahrens, a postdoctoral researcher at the University of Florida Institute of Food and Agricultural Sciences, the study findings could help identify the bacteria that should be examined or monitored when dealing with mental health issues.

“These results are exciting because they tell us which bacteria we need to look at more closely. Our question now is, what are these bacteria doing biologically that affects mental health?” Ahrens said in a press release.

“Eventually, we hope this line of research could help predict suicidal ideation based on a person’s microbiome and could inform pro- or prebiotic treatments for those at risk,” she added.

For the study, students had to go to the lab to provide their saliva samples. The researchers have since developed a collection kit participants can use when collecting samples at home.