Ok Marijuana is NOT ADDICTIVE people. You don't go through withdrawal symptoms when you're not on Marijuana for a length of time. Other drugs that are addictive will give you withdrawal symptoms when you're not on them.
Now with that said, Marijuana can be habit forming like nail biting. Can it be harmful? Absolutely. if you would rather get high all the time instead of spending time with friends or family then you're looking for trouble.
From our personal experience it has been just great. My husbands migraines have nearly disapeared. Instead of 1 a week he gets maybe 5 migraines a year, but my husband does admit that occasionally he has had some issues with recalling important details at his job after he's been high.