Eric Harris was taking Luvox at the time of the Columbine massacre. Dylan Klebold's medical records have been sealed, but the anger-management classes he and Eric were both taking would have required his use of anti-depressants.
Prescription Psychiatric Drugs Triggered Columbine Killings!
When such extremely violent incidents are perpetrated by kids who are on psych meds, it's because:
1) They're crazy in the first place, which is why they're on the meds, and
2) While the meds can be helpful, they are no magic bullet, but unfortunately they are being treated as if they are -- a kid who's seriously crazy and unstable is sent off to a regular school with no supervision, so long as he's on his meds.
The latter is just one of many types of ill-advised "mainstreaming" that has become the norm in education in our day. The education and government establishments have got it into their heads that all kids should go to the same schools, no matter how how severe their mental and/or physical impairments. Even the ones who are attending special schools are, with rare exceptions, doing so under an "individualized education program" that is explicitly aimed at getting them into a normal school as soon as possible. We need to bring back the idea that normal schools and normal home life arrangements are for normal kids.