Researchers have created an AI-based tool that can predict mood disorder episodes using sleep-wake data recorded by wearable devices such as smartwatches. This innovation promises a cost-effective and clinically applicable approach to diagnosing and treating mood disorders, which include conditions like bipolar disorder. These disorders are often marked by extended periods of depression, mania, or hypomania, all of which are closely tied to disruptions in circadian rhythms, the natural cycles that regulate sleep and wakefulness.