Mood instability in bipolar disorder type I versus type II-continuous daily electronic self-monitoring of illness activity using smartphones

•Patients with BD often remain symptomatic in inter-episodic periods.•A smartphone-based monitoring system was used by patients with BD.•Patients with BD II experienced lower levels of mood compared to BD I.•Patients with BD II experienced less time euthymic compared to BD I.•This emphasizes the need for improving treatment strategies for BD type II.