I smoked pot every single day, pretty much all day, for about 17 years straight.
When i eventually stopped, i had some symptoms of withdrawal. Yes, i definately had a psychological 'need' for it, for instance, it's completely fucked up my sleep regime to this day - i cannot sleep properly at night, and i've been stopped now for about 5 years. I got into the routine of getting so baked until i fell asleep, when i eventually stopped, it was as if my brain couldnt switch off, and i still suffer from major insomnia now.
For a few weeks after i stopped, i would get crazy hot flushes, sweats, irritated skin, symptoms that at the time felt pretty physical to me. Psychologically i was a mess, it'd take just the tiniest of things to send me into a rage, my brain was foggy etc, It took a long time for me to get used to not smoking it.
I remember also getting some fucked up dreams (when i went to bed stoned, i wouldnt dream, so after stopping smoking the dreams came back with a vengeance), I'd get shaking fits when i was asleep. I'd wake up confused, shaking, sweating buckets.....
I'm not a doctor, and i know everyone's experience is different, but personally when i came off of weed after smoking it so regularly for so long, it definately felt like i was having physical and mental withdrawals.