Nightmare disorder and recurrent isolated sleep paralysis are rapid eye movement (REM) parasomnias that cause significant distress to those who suffer from them. Nightmare disorder can cause insomnia due to fear of falling asleep through dread of nightmare occurrence. Hyperarousal and impaired fear extinction are involved in nightmare generation, as well as brain areas involved in emotion regulation. Nightmare disorder is particularly frequent in psychiatric disorders and posttraumatic stress disorder. Nonmedication treatment, in particular imagery rehearsal therapy, is especially effective. Isolated sleep paralysis is experienced at least once by up to 40% of the general population, whereas recurrence is less frequent. Isolated sleep paralysis can be accompanied by very intense and vivid hallucinations. Sleep paralysis represents a dissociated state, with persistence of REM atonia into wakefulness. Variations in circadian rhythm genes might be involved in their pathogenesis. Predisposing factors include sleep deprivation, irregular sleep–wake schedules, and jetlag. The most effective therapy consists of avoiding those factors.

噩梦症和复发性孤立性睡眠麻痹是快速眼动 (REM) 异态睡眠，会给患者带来严重的痛苦。噩梦症可因害怕噩梦发生而不敢入睡而导致失眠。过度警觉和恐惧消退受损与噩梦的产生以及参与情绪调节的大脑区域有关。噩梦障碍在精神疾病和创伤后应激障碍中尤其常见。非药物治疗，特别是想象排练疗法尤其有效。多达 40% 的普通人群至少经历过一次孤立性睡眠瘫痪，但复发的频率较低。孤立性睡眠麻痹可能伴有非常强烈和生动的幻觉。睡眠麻痹代表一种分离状态，持续快速眼动肌无力直至清醒。昼夜节律基因的变异可能与其发病机制有关。诱发因素包括睡眠不足、不规律的睡眠-觉醒时间表和时差反应。最有效的治疗方法是避免这些因素。