And there's the rub. To really validate the theory, there needs to be a comparison of the overall number of users (say of cocaine or heroin) to the number of users who have committed other crimes. Unfortunately, both numbers are uncertain. Still, I'm open to facts, if they're out there.
I have not known one single HARD drug user that I would have said was acting responsibly and with reason while high on the narcotic, at any level of use.
May I ask which hard drugs you are referring to?