Kill them?
Yikes, never heard of that.
By 'mind-altering', I don't necessarily mean drugs. Just the way you talk and behave could get them to change their focus and stop those repetitive thought patters. This is usually out of genuine necessity to help really. I've never found sympathizing and reasoning to work that well. Usually it's when they feel better and 'cheer up' is when they change their minds and make better decisions.