One can be taking responsibility, getting help, testing clean week after week, month after month, and slip up one time with the wrong people or when depressed, and get right back on the wagon, yet be suspended at the next level. That's addiction....it's not necessarily weed addiction; it's addictive behavior and self-medication due to depression.
Not all drunks are alcoholics physically; some are binge drinkers who self-medicate to feel better. Most weed smokers aren't as addicted to the weed as they are medicating and chasing a feeling of peace that's missing. They need lots of counseling, not just a detox period. Drug addicts, even after kicking a physical addiction, still take years to learn how to be happy and not relapse into self-medicating when they are sad or lonely.