Social rhythm disruption is associated with greater depressive symptoms in people with mood disorders: Findings from a multinational online survey during COVID-19

Objectives Societal restrictions imposed to prevent transmission of COVID-19 may challenge circadian-driven lifestyle behaviours, particularly amongst those vulnerable to mood disorders. The overarching aim of the present study was to investigate the hypothesis that, in the routine-disrupted environment of the COVID-19, amongst a sample of people living with mood disorders, greater social rhythm disruption would be associated with more severe mood symptoms. Methods We conducted a two-wave, multinational survey of 997 participants [Formula: see text] who self-reported a mood disorder diagnosis (i.e., major depressive disorder or bipolar disorder). Respondents completed questionnaires assessing demographics, social rhythmicity (The Brief Social Rhythm Scale), depression symptoms (Patient Health Questionnaire-9), sleep quality and diurnal preference (The Sleep, Circadian Rhythms and Mood questionnaire) and stressful life events during the COVID-19 pandemic (The Social Readjustment Rating Scale). Results The majority of participants indicated COVID-19-related social disruption had affected the regularity of their daily routines to at least some extent ( n = 788, 79.1%). As hypothesised, lower social rhythmicity was associated with greater depressive symptoms when tested cross-sectionally (standardised β = −.25, t = −7.94, P = 0.000) and when tested using a 2-level hierarchical linear model across two time points ( b = −0.14, t = −3.46, df = 264, P ≤ 0.001). Conclusions These results are consistent with the social zeitgeber hypothesis proposing that mood disorders are sensitive to life events that disrupt social rhythms.