I hadn't smoked marijuana in about 37 or so years. I decided to try it to help with chronic pain. It's allowed me to throttle back my morphine by 2/3rds.
Here's the hitch. If I stop smoking marijuana by the 4[SUP]th[/SUP] day I'm showing opiate withdrawal symptoms. 1 puff and the opiate withdrawals, piloerection, increased peristalsis, restless leg, runny nose all stop. Marijuana potentiates the cytochrome p450 system and is synergistic with opiates. So now I am physically dependent upon marijuana if I want the opiate withdrawals kept at bay as the far reduced dose.
So no marijuana itself is not physically addictive but it can potentiate opiates and create psychological habituation.