Title: Polygenic Scores, Sleep, Activity and Family History as Predictors of Major Mood Disorders
Speaker: Kathryn Freeman, Research Assistant | FORBOW Project, PhD Candidate, Medical Neuroscience, Dalhousie University
Date: Tuesday, October 7, 2025
Time: 11:30am - 12:30pm
Location: 3H-01, Tupper Building (3rd floor)
Description: Mood disorders, including major depressive disorder and bipolar disorder, are one of the most common sources of long-term disability globally. Although positive family history and early childhood diagnoses predict later mood disorders, they alone fail to reach clinically meaningful accuracy. Aberrant sleep and activity are both symptoms and probable contributing factors to the development of mood disorders, highlighting their potential as modifiable risk factors. We aimed to reveal the contributions of genetics, sleep and activity to the onset of mood disorders in adolescence. First, we explored how subjective and objective measures of sleep and physical activity relate to familial risk for mood disorders. We found that subjective measures of sleep and activity hold distinct relationships with familial risk, indicating value captured through qualitative data. Second, we revealed that multiple genetic scores in a European sample were associated with mood disorder onset above known predictors, family history and early psychopathology. Third, we improved inclusivity, providing replicable associations of multiple genetic scores with onsets of major mood and psychotic disorders in diverse populations, expanding to sleep and activity phenotypes. We show unweighted genetic score averages reduce biases that could arise through any single method of scoring in diverse ancestry. Finally, we investigated polygenic sleep-activity divergence as a potential risk factor for mood disorders. Self-reported sleep that was poorer than expected based on genetic predisposition was linked to family history of mood disorders and even more strongly associated with mood disorder onset. Overall, these results advance the understanding of genetic contributions to mood disorder onset and their interplay with putative modifiable risk factors, sleep and physical activity.