Where can I find information about psychological addictions to marijuana?

You just have the thought of addiction stuck in your head, I've smoked for years at times more than others and I've gone months without it. When I've gone without it, I don't feel the need to do it, I'm just really bored. When I stopped drinking it was a lot different, that was much, much, harder and I had physical symptoms as well, not just a need to drink.