Sleep Disturbances and Mental Health: A Transdiagnostic View of Sleep Disorders Symptoms in a Representative Canadian Sample

ABSTRACT

Introduction: Sleep problems can actively contribute to the onset, maintenance and worsening of mental disorders. Beyond insomnia, several other sleep pathologies may be associated with adverse mental health outcomes, and having multiple sleep disorders may be an aggravating factor. This study aimed to delineate the current landscape of sleep difficulties and symptoms of sleep disorders linked to poor mental health, investigate associations between the age at onset of sleep problems and subsequent mental health, and assess the perceived impacts of sleep problems. Materials and Methods: A representative sample of 1,200 Canadians (16 to 88 years old, 53% females) completed an online survey on sleep and mental health between 21 and 24 September 2021 (i.e. after the acute phase of the COVID-19 pandemic in Canada). The survey included questions inspired form the Sleep Disorders Questionnaire, Sleep Disorders Symptom Checklist-25, Pittsburgh Sleep Quality Index, STOP-Bang, and Insomnia Severity Index. The sample was stratified in two groups based on self-reported current mental disorder diagnosis mental disorder diagnoses [219 (18.2%)] vs no diagnosis [960 (80.0%)]. Total scores on the General Anxiety Disorder-7 and Patient Health Questionnaire were used to determine anxiety and depression symptoms severity. Results: Of those with mental disorder diagnoses, 80.4% (176/219) endorsed symptoms of at least one sleep disorder, a proportion significantly higher compared to the 42.7% observed in the rest of the sample (p<.001, V=.29). The mental disorder diagnoses group included higher proportions of respondents endorsing symptoms of insomnia disorder, sleep apnea, bruxism, restless legs syndrome, nightmare disorder, hypersomnia and somnambulism. After adjusting for age, sex, income level and total sleep time, having a mental disorder diagnosis was associated with insomnia (OR=3.52, p<.001), obstructive sleep apnea (OR=1.95, p=.006) and bruxism (OR=2.77, p<.001). Half of those with mental disorders diagnoses endorsed symptoms of multiple sleep disorders, a proportion significantly higher than what was observed in the rest of the sample (p<.001, V=.35). Endorsing symptoms of insomnia, sleep apnea, bruxism, restless legs syndrome, and hypersomnia were associated with more severe anxiety and depression symptoms after adjusting for age, sex, income level, total sleep time, and mental disorders diagnoses (B>.98, p<.012). Younger age at onset of sleep problems was a significant independent predictor for current self-reported diagnosis of mental disorders (OR=.96, p<.001). Compared to the rest of the sample, the mental disorder group reported significantly worse impacts of sleep problems on mental health, family relationships, physical health, cognitive functioning, productivity level, and global daily functioning. Conclusions: These results reinforce the transdiagnostic nature and cumulative impacts of the various profiles of sleep problems associated with mental health issues. These findings also suggest that the relationship between sleep and mental health is not solely driven by short sleep duration or insomnia. There is a need to enhance awareness about the diverse profiles of sleep issues linked to poor mental health and the relevance of early intervention, notably during youth. Should future longitudinal studies based on objective measures confirm these observations, this may inform further development of transdiagnostic sleep interventions for people with mental disorders.