Addiction - Can opiate addiction turn a normal citizen into a dangerous criminal?

[cybergenesis]

Here is a question for all of you. On the news you often hear of heroin and opiate addicts robbing people, robbing banks, etc...

How strong is the addiction to heroin? or say to other opiates? Can it make say a gentle, law abiding geek turn into a dangerous, violent felon? Or are the addicts that become like that otherwise violent and misguided in the first place? Is such behavior just because many people who get addicted come from rough backgrounds where they have been socialized in the ways of crime?

I know many addicts steal and lie to some degree to get drugs. They may pawn of their possessions, but how far can the addiction twist an otherwise "straight" person?