Day-to-day variability in activity levels detects transitions to depressive symptoms in bipolar disorder earlier than changes in sleep and mood. - Ortiz, Abigail; Halabi, Ramzi; Alda, Martin; DeShaw, Alexandra; Husain, Muhammad I.; Nunes, Abraham; O'Donovan, Claire; Patterson, Rachel; Mulsant, Benoit H.; Hintze, Arend (International Journal of Bipolar Disorders, 2025)