Sanchez, Amanda L. et al. Journal of the American Academy of Child & Adolescent Psychiatry , Volume 0 , Issue 0 , Published online December 2017.  DOI: http://dx.doi.org/10.1016/j.jaac.2017.11.022

This systematic review of 43 schools and almost 50,000 elementary (primary) school-aged children demonstrates that targeted interventions and those implemented multiple times a week are more effective than interventions designed for selective or universal prevention in this age group.

http://www.jaacap.com/article/S0890-8567(17)31926-3/fulltext