Da Silva MA, et al. - Using data from the prospective cohort study of the Population Assessment of Tobacco and Health waves 1 (September 12, 2013, to December 14, 2014) and 2 (October 23, 2014, to October 30, 2015), a nationally representative sample of youth, the bidirectional association between bullying perpetration and internalizing problems was evaluated among youth in the U.S. The analysis suggests a bidirectional association between bullying perpetration and internalizing problems. Researchers identified the correlation of bullying perpetration with an increased likelihood of moderate/high internalizing problems at follow-up and observed higher odds of bullying perpetration at follow-up among youth with moderate/high internalizing problems.