The study, published in the Journal of Adolescent Health, found nearly 40 percent of young adults who said they had tried suicide said they made their first attempt before entering high school.
Lead author James Mazza of the University of Washington and colleagues found suicide attempts during childhood and adolescence were linked to higher scores of depression at the time of the attempts.
"Young adults who end up having chronic mental health problems show their struggles early," Mazza said in a statement. "This study suggests that implementation of mental health programs may need to start in elementary and middle schools, and that youth in these grades are fairly good reporters of their own mental health."
Mazza and colleagues asked 883 young adults age 18-19 about their history of suicide attempts and nearly 9 percent said that they had tried suicide at some point. Suicide attempt rates showed a sharp increase around sixth grade, about age 12, with rates peaking around eighth or ninth grade, the study said.
However, for the 39 respondents reporting multiple suicide attempts, their first attempt was significantly earlier -- as young as 9 -- than for those making a single attempt, Mazza said.