nostr:npub160ed0rgndfqggfnn2vmqwjuvxan6h6d6dul2x6arq2f3p0qwnvfqqnc04e It can fuck with dopamine or serotonin or something, depending on how heavily it's been used. As in when you stop smoking you get super emotional for no reason and might have trouble sleeping - or sleeping too much for a few days.
Then once your receptors unfuck themselves you'll start dreaming again.
Studies routinely (iirc) fail to find a reason for the "addiction" but some people are addicted to gambling, too.