It was saying, it was your fault. I think it was your post, apologize if not.
But yes, its important to do some reading at aites like National Institute Drug Abuse and its one place you can see brain scans and read about how drugs affect the regions of the brain. The brain controls the emotions, and ability to reason and all those good things.
Of course sometimes people are nasty in various ways even without drug use. That one is for you to figure out too.