WashU Medicine Oct 16 2025 A new study from researchers at Washington University School of Medicine in St. Louis provides some answers. Published Sept. 15 in Nature Mental Health , it mined an enormous set of data collected from pre-teens and teens across the U.S. and found that social conflicts - particularly family fighting and reputational damage or bullying from peers - were the strongest predictors of near- and long-term mental health issues. The research also revealed sex differences in