Chapter 8: Eating and Sleep–Wake Disorders

Eating disorders are defined by severe disturbances in eating behaviors and body image perception, driven by intense anxiety about weight gain and appearance. Anorexia nervosa involves dangerous food restriction coupled with distorted body image and an overriding fear of gaining weight, and requires comprehensive treatment including nutritional restoration, psychotherapy, and exposure-based interventions for weight-related fears. Bulimia nervosa is characterized by cycles of binge eating followed by compensatory purging behaviors such as self-induced vomiting, excessive exercise, or laxative misuse, and responds well to cognitive-behavioral approaches alongside pharmacological treatment with selective serotonin reuptake inhibitors. Binge-eating disorder presents as recurrent episodes of uncontrolled eating without the compensatory behaviors seen in bulimia, and benefits from cognitive-behavioral therapy and self-monitoring techniques. The etiology of eating disorders involves multiple contributing factors across biological, psychological, and sociocultural domains, including genetic vulnerability, neurochemical imbalances involving serotonin regulation, personality traits such as perfectionism, emotional dysregulation, and cultural pressures emphasizing thinness. Sleep-wake disorders comprise two major categories: dyssomnias involving abnormal sleep quantity or quality, and parasomnias involving unwanted behaviors during sleep. Insomnia disorder reflects chronic difficulty initiating or maintaining sleep and responds to cognitive-behavioral interventions, sleep hygiene modification, and circadian rhythm regulation. Hypersomnolence disorder involves excessive daytime sleepiness independent of nighttime sleep duration and requires stimulant medications. Narcolepsy presents as sudden sleep attacks often accompanied by cataplexy, a sudden loss of muscle tone triggered by emotion. Sleep apnea involves repeated breathing interruptions during sleep with serious cardiovascular consequences and is managed through continuous positive airway pressure technology. Circadian rhythm sleep-wake disorder emerges when sleep timing conflicts with environmental demands or individual physiology. Parasomnias such as nightmare disorder, sleepwalking, sleep terrors, and rapid eye movement sleep behavior disorder involve abnormal experiences or actions during sleep states. Treatment approaches vary across disorders but frequently incorporate behavioral interventions, pharmacological agents targeting neurotransmitter systems, and lifestyle modifications to restore healthy functioning.