Sleep-wake disorders are conditions that impact the quality, timing, and duration of sleep, leading to daytime distress and functional impairments, often occurring alongside medical or mental health issues. Examples include insomnia, sleep apnea, and narcolepsy, classified under DSM-V, ICSD-3, and ICD-10, focusing on non-organic types. Causes typically involve disruptions in the body's circadian rhythms, resulting in symptoms such as excessive daytime sleepiness and irregular sleep cycles.