Bipolar disorder (BD) is a mental health condition that causes extreme mood swings from elevated (mania, hypomania) to diminished state (depression), as well as mixed episodes, where depression and manic symptoms occur together. Its diagnosis is performed through a set of medical examinations administered by the psychiatrist but may require lengthy observations of the patient as there is no comprehensive test. There is a lot of co-morbidity with other mental disorders including, but not limited to, any anxiety disorder, conduct disorder, and substance use disorder. The disease affects 2% of the population, sub-threshold forms (recurrent hypomania episodes without major depressive episodes) affect an additional 2%, and together, the lifetime prevalence estimates are 4.4%. It is ranked as one of the top ten diseases of disability-adjusted life year indicator among young adults, and as the 17th leading source of disability among all diseases worldwide.

Diagnosis of mental health disorders rely on medical examinations administered by psychiatrists and reports from patients and their relatives or friends. But there is a need for more systematic and objective diagnosis methods, for remote treatment and diagnosis approaches assisted using automated methods. It is possible to collect behavioral data from people during their everyday lives, which creates an opportunity to create tools to monitor the symptoms of the patients for longer periods, screen patients before they see the psychiatrists, assist clinicians in the diagnosis, and capture patient behaviors in situations where they cannot act or hide the symptoms.