Actually marijuana is not addictive.
> Apparently, not everyone agrees:http://www.marijuana-anonymous.org/
It is impossible to become physically addicted to marijuana, however one can become *psychologically* (you believe you need it)... just as one can become "addicted" to video games.
I will admit that if one uses marijuana all day every day for a solid year and then one abruptly quits, one might experience a week of symptoms similar to quitting coffee.