Abstract
Objective: Insomnia and depression are prevalent disorders that often co-occur. This study aimed to investigate the impact of clinically significant insomnia symptoms on the prevalence and clinical presentation of clinically significant depressive symptoms and vice versa.Methods: This study used data from the Korean Headache-Sleep Study (KHSS), a nationwide cross-sectional population-based survey regarding headache and sleep. Clinically significant insomnia symptoms were defined as Insomnia Severity Index (ISI) scores ≥ 10 and clinically significant depressive symptoms were defined as Patient Health Questionnaire-9 (PHQ-9) scores ≥ 10, respectively. We referred clinically significant insomnia symptoms and clinically significant depressive symptoms as insomnia symptoms and depressive symptoms, respectively.Results: Of 2,695 participants, 290 (10.8%) and 116 (4.3%) were classified as having insomnia and depressive symptoms, respectively. The prevalence of depressive symptoms was higher among participants with insomnia symptoms than in those without insomnia symptoms (25.9 vs. 1.7%, respectively, P < 0.001). Among participants with depressive symptoms, the PHQ-9 scores were not significantly different between participants with and without insomnia symptoms (P = 0.124). The prevalence of insomnia symptoms was significantly higher among participants with depressive symptoms than in those without depressive symptoms (64.7 vs. 8.3%, respectively, P < 0.001). The ISI scores were significantly higher among participants with insomnia and depressive symptoms than in participants with insomnia symptoms alone (P < 0.001).Conclusions: Participants with depressive symptoms had a higher risk of insomnia symptoms than did those without depressive symptoms. The severity of depressive symptoms did not significantly differ based on insomnia symptoms among participants with depressive symptoms; however, the severity of insomnia symptoms was significantly higher in participants with depressive symptoms than in those without depressive symptoms.
Highlights
Depression is a common mental health disorder that affects approximately 4.4% of the global population [1]
We evaluated the impact of insomnia symptoms on the prevalence of depressive symptoms by calculating the age- and sex-adjusted odds ratio (OR): the ratio of the odds of having depressive symptoms in participants with insomnia symptoms to the odds in participants without insomnia symptoms, as determined, using logistic regression analyses
We evaluated the impact of depressive symptoms on the clinical presentation of insomnia symptoms by comparing the severity of insomnia (ISI score) between participants with insomnia symptoms who had and did not have depressive symptoms using multiple linear regression analyses after adjusting for age and sex
Summary
Depression is a common mental health disorder that affects approximately 4.4% of the global population [1]. Owing to its disabling symptoms and comorbidities, individuals with depression experience an increased risk of functional impairment and decreased quality of life [2]. According to the Global Burden of Diseases Study 2015, depression was ranked as the third leading cause of disability among 310 disorders and injuries [3]. Insomnia is a prevalent disorder that affects 9–15% of the general population [4]. Insomnia has significant negative effects on various aspects of human functioning and is associated with greater disability at work, school, and home [5]. Individuals with insomnia reportedly use more health care services [6]
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