I smoked weed regularly for 4-5years, it got to the point where it was undeniably an addiction, call it mental or psychological, whatever, but I was dependant on it.
It can be a good portal to open doors in your ability to percieve society/self in an more spiritual/intuitive way. but I believe once those doors have been opened, and that awareness is gained, you no longer 'need' to smoke marijauna to access that insight. Over time, from my experience, it diminishes memory/vocabulary, and in most cases, is amotivational.
I know, that if you are disciplined, and can use on occasion, in moderation, it can still be a productive experience, but on a day to day scale,
i think the unseen repercussions, such as inability to pursue long term goals due to herb being more important, make it an addiction of sorts.
I'm also one of those individuals who gradually became paranoid/introverted after getting high, and over time would only smoke by myself.