O051 Insomnia predicts persistent symptoms of anxiety and depression during the COVID-19 pandemic: A 12-month longitudinal cohort study

INTRODUCTION: Insomnia increases risk of affective disorders. This study assessed whether individuals with insomnia symptoms at the beginning of the pandemic, either new-onset or pre-existing, were at increased vulnerability to anxiety and depressive symptoms longitudinally compared to those who continued sleeping normally. Sleep-related factors (e.g., pre-sleep arousal) were also examined for their influence on risk of clinically significant anxiety and depression. METHOD: Between April 2020 and May 2021, 2069 participants (M=46.16 years, SD=13.42; 75.3% female) with new-onset, pre-existing, or no insomnia symptoms responded to a global online survey with 3-, 6-, and 12-month follow-ups. Data were analysed using mixed-effects and logistic regression models. RESULTS: New-onset and pre-existing insomnia were stronger predictors of anxiety and depressive symptoms over time (p’s <.001) than other established risk factors such as, age, sex, and past psychiatric diagnoses. Although depressive symptoms in both insomnia groups declined from acutely elevated baseline levels, they remained clinically significant at the majority of timepoints whereas normal sleepers remained below threshold. Pre-sleep arousal was identified as a risk factor for clinically significant symptoms of anxiety (OR=1.05) and depression (OR=1.09) at 12-months. Sleep effort predicted anxiety (OR=1.06), whereas dysfunctional sleep-related attitudes and beliefs contributed to clinically significant depression (OR=1.22). DISCUSSION: Insomnia and associated sleep-related factors are key modifiable risks for persistent symptoms of anxiety and depression. This study highlights sleep as an opportunity for intervention into the enduring mental health ramifications of the COVID-19 pandemic and underlines the need to integrate insomnia treatment into routine mental health care.