For the study, researchers from the University of Washington analyzed data "from a larger National Institute of Drug Abuse 15-year study of youth in a Seattle-area school district" that examined "risk factors for marijuana and cigarette use, binge drinking, depression, and past suicidal behavior."

The investigators found that "depression during high school and a previous suicide attempt were significant predictors of thinking about suicide one or two years later." But, "young people who were depressed or had attempted suicide in high school were less likely to have suicidal thoughts if they had strong family support and bonds. Having a girlfriend or boyfriend also helped."