Based on a review of the deaths documented on Wikipedia, the vast majority of deaths could have been avoided by following these simple steps:

1. Don't be a prostitute.
2. Don't do drugs and hang around with people who do drugs.
3. Don't associate with criminals who have illegal guns.

It would eliminate almost every murder and, strangely enough, the same advice works for any demographic of people! It's almost as if these deaths are more due to lifestyle than mental health issues.