Depressed people are often suicidal. Maybe the medication wasn’t strong enough?
Practically every single mass school shooting from 1989 onwards it comes out that the perpetrator has been found to be on suicide pills. Previously there weren’t that many ‘mass’ school shootings, most school shootings were by a disgruntled student or fired teacher and only one or two killed or wounded. (check wikipedia “history of school shootings).
1989 was the year Prozac was released and then big pharma push began.