Here are the last major school shooters and the link under each name is a reputable news source that connects them all with SSRI's (selective serotonin reuptake inhibitors) like Prozac, Ritalin, and others:
1) May 20 1999: T.J. Solomon, a 15-year-old wounds six at Heritage High School in Conyers, Ga.. http://www.msnbc.com/news/274480.asp
2) April 16 1999: Shawn Cooper, a 15-year-old sophomore wounds one at Notus Junior-Senior High School in Notus, Idaho. http://www.boiseweekly.com/archive/v7i42/cope/cope_col.html
3) April 20 1999: Eric Harris and Dylan Klebold kill thirteen and wound twenty three at Columbine High School. http://www.washingtonpost.com/wp-srv/national/daily/april99/antisocial04299.htm
4) May 21, 1998: Kip Kinkel, a 15-year-old kills four and wounds twenty three at Thurston High School in Springfield, Ore.. http://www.drugawareness.org/washtimes.html