Bullying is costly with serious, long lasting consequences. Victims have high levels of depression, anxiety and suicidal thoughts. Sometimes they carry through with those thoughts. http://www.jaredstory.com/bully.html.
Up to 15% of bullied children require intervention and support.
Reactions to bullying can be deadly. http://ceep.indiana.edu/projects/PDF/PB_V1N5_Bullying.pdf. See also: http://www.stateline.org/live/ViewPage.action?siteNodeId=136&languageId=1&contentId=15595.
In 2002, the Secret Services reported that nearly 75% of attackers in school shootings reported being bullied. http://www.secretservice.gov/ntac/ssi_final_report.pdf.
Reflecting on the numbers, one wonders why there are not more school shootings.