True about REM sleep is

ParasomniasParasomnias are dysfunctions or episodic nocturnal events occurring with sleep, sleep stages or paial arousals. Most parasomnias are common in childhood though they may persist into adulthood.Stage 4 Sleep Disorders:These disorders occur during deep sleep, i.e. Stages 3 and 4 of NREM-sleep.Nightmares (which occur during REM sleep) are clearly remembered in the morning. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 140