Identifying Mood Instability and Circadian Rest-Activity Patterns Using Digital Remote Monitoring and Actigraphy in Participants at Risk for Bipolar Disorder.

INTRODUCTION: Mood and/or affective instability and circadian rhythm disruptions are increasingly recognised in psychiatric disorders, notably bipolar disorder (BD), but their interrelationship remains unclear. By definition, both have an integral temporal component and, as such, measuring them longitudinally and remotely is desirable. METHODS: We assessed the feasibility and value of digital devices to capture mood and subjective state (affect) instability and daily rest-activity patterns over a 10-week period in two groups of participants. The first group (n = 37) scored > 7 on the Mood Disorder Questionnaire (MDQ) ('high MDQ'), indicating a history of mood elevation and increased risk for BD. They were compared with a group (n = 37) scoring < 5 on the MDQ ('low MDQ'). Over the 10-week period, mood was rated daily, clinical ratings of depression, mania and anxiety were captured weekly, and a GENEActiv actigraph was worn to collect rest-activity pattern data. RESULTS: The main findings were that (1) MDQ score predicted instability in mood and subjective state; (2) high MDQ score was associated with greater negative affect, mood symptoms and altered circadian activity profiles compared with low MDQ; and (3) mood and subjective state instability appeared unrelated to circadian indices. CONCLUSION: These findings suggest that (1) remote monitoring of these domains is feasible and valuable; (2) selection of participants based on MDQ score is useful for studying mood and affective instability; and (3) this approach has potential utility for clinical and experimental medicine studies assessing interventions targeting mood dysregulation and affective instability.