I'm a former cigarette smoker (smoked nearly 3 packs a day) been clean now for nearly 5 years and I say with 100% certainty that Weed is NOT physically addictive. It's psychologically addictive. But your body never thinks it "needs" it. Only your mind. The topic creator clearly has mistook psychological symptoms for physical ones.

You can mentally become used to feeling high at certain times, in certain situations and it becomes where you feel you need it. Going without weed would then make you irritable, and probably depressed as you are mentally used to being high. Being depressed can cause you to feel ill and give you physical symptoms.

But it's still only in your mind.