Sleep is increasingly understood as a local brain phenomenon, not just a whole-brain process, with different states of consciousness—wakefulness, sleep onset, light sleep, deep sleep, and REM sleep—able to occur simultaneously, leading to dissociative states. These are classified as physiological (daydreaming, lucid dreaming, false awakenings), pathological (sleep paralysis, sleepwalking, REM sleep behavior disorder), and altered (hypnosis, anesthesia, psychedelics). The article reviews the neurophysiology and phenomenology of these states, concluding that their study is important for understanding consciousness and treating neuropsychiatric diseases.
A brief intervention combining imagery rehearsal therapy with narrative therapy principles reduced nightmare frequency and intensity in eight veterans with PTSD-related nightmares. After a single 60-minute rescripting session and four weeks of homework, participants reported significant decreases in nightmare frequency and intensity, along with improvements in nightmare distress, coping, sleep quality, and overall PTSD symptoms. These pilot results suggest the approach is effective for veterans, though larger controlled trials are needed to confirm effectiveness.