Irregular Sleep-Wake Rhythm Disorder (ISWRD)

Irregular sleep-wake rhythm disorder (ISWRD) is a rare circadian rhythm disorder where a person lacks a defined 24-hour, sleep-wake cycle, resulting in fragmented, unpredictable, and sporadic naps and waking periods throughout the day and night. While the total daily sleep time is often normal, it’s broken into 2-4 hour chunks, causing chronic insomnia, excessive daytime sleepiness, and, frequently, neurological issues. ISWRD stems from a weakened internal circadian signal combined with weak environmental cues (like lack of sunlight or low physical activity), which fails to entrain the body to a day-night cycle is commonly associated with neurological conditions (Alzheimer’s, dementia, Parkinson’s, brain injury) that damage the brain’s clock (suprachiasmatic nucleus/SCN). It’s also common in people with serious mood disorders, like bipolar disorder (BD).