Because nicotine was suppressing REM sleep for years, and the brain, finally released from that suppression, is compensating with an intensity of dreaming that feels alarming but is actually recovery.

The acute disruption peaks in the first week and resolves meaningfully by weeks two to three. Full sleep quality restoration, which is better than the smoking baseline, typically completes within one to three months.

Yes, increased sleep need in early cessation is common and has specific neurological and physiological explanations that make it expected rather than concerning.

Because the sleep after quitting is not yet fully restorative, the same withdrawal that disrupts waking function also disrupts the sleep architecture that makes sleep regenerative.