Circadian Rhythm Sleep Disorder: Irregular Sleep Wake Rhythm

Irregular sleep–wake rhythm disorder (ISWRD) is characterized by the relative absence of a circadian pattern in an individual's sleep–wake cycle. ISWRD is thought to result from some combination of degeneration or decreased neuronal activity of suprachiasmatic nucleus neurons, decreased responsiveness of the circadian clock to entraining agents such as light and activity, and decreased exposure to bright light and structured social and physical activity during the day. Studies of the effectiveness of pharmacologic treatments for ISWRD generally have yielded negative or inconsistent results. In general multimodal nonpharmacologic approaches involving increased exposure to light, increased physical and social activities, and improved sleep hygiene have been the most successful therapeutic approaches.