Sleep quality, insomnia symptoms, chronotype, and mental health in young adults

There is a bidirectional relationship between sleep and mental health, with deteriorations in one often associated with concomitant decrements in the other. Young adults (YAs) are at an increased risk of experiencing sleep disturbance, as well as anxiety and mood disorders. Individuals at this developmental stage are also more likely to have an evening chronotype, the circadian preference most closely related to poor mental health outcomes. This dissertation comprises two studies that draw from the same data set. Study 1 examined the prevalence rates of, and relationships among, sleep disturbance as measured by three sleep metrics and mental health. Results from this first study demonstrated above average rates of anxiety, depression, and global distress. A dose-response relationship was found between sleep disturbance, as indicated by three separate sleep metrics, and mental health symptoms: the greater the number of sleep measures for which participants met or exceeded clinical cut-offs, the more severe was the mental health symptomology. Study 2 examined the prevalence rates of chronotype among YAs, and the relationship between chronotype and symptoms of anxiety, depression, and global distress, as well as the positive psychological constructs of mindfulness and perceived social support. The second study demonstrated a prevalence rate of evening chronotype that is consistent with other YA populations surveyed elsewhere. Additionally, it was found that chronotype shared a gradient relationship with mental health, with evening types endorsing greater scores on all mental health measures than their intermediate and morning counterparts. In contrast, morning types were more likely to report greater levels of mindfulness and perceived social support. Age had an inconsistent impact on the relationship between chronotype and mental health. This findings of these two studies emphasize the increased risk at which YAs with poor sleep quality and/or evening chronotype are for experiencing symptoms of depression, anxiety, and distress. Study limitations and future directions for knowledge translation are discussed