If we're trying to find a reason for these kids shooting up schools, outside of parenting issues, I'd be more likely to look into the drugs they are being given that to look at violent games/movies. What percentage of school shooters were on some sort of psychotropic drug?
From the National Institute of Mental Health:
What are the possible side effects of antidepressants?
Some antidepressants may cause more side effects than others. You may need to try several different antidepressant medications before finding the one that improves your symptoms and that causes side effects that you can manage.
The most common side effects listed by the FDA include:
- Nausea and vomiting
- Weight gain
- Diarrhea
- Sleepiness
- Sexual problems
Call your doctor right away if you have any of the following symptoms, especially if they are new, worsening, or worry you(U.S. Food and Drug Administration, 2011):
- Thoughts about suicide or dying
- Attempts to commit suicide
- New or worsening depression
- New or worsening anxiety
- Feeling very agitated or restless
- Panic attacks
- Trouble sleeping (insomnia)
- New or worsening irritability
- Acting aggressively, being angry, or violent
- Acting on dangerous impulses
- An extreme increase in activity and talking (mania)
- Other unusual changes in behavior or mood
https://www.nimh.nih.gov/health/topics/mental-health-medications/index.shtml