The Mediating Effect of Depression in the Relationship between Sleep Misperception and Insomnia Severity among Insomnia Patients

ABSTRACT

Objectives@#Sleep misperception is the underestimation of perceived total sleep time compared to actual total sleep time. It is observed in approximately 50% of patients with insomnia. Insomnia patients with sleep misperception report significantly higher depression than those without sleep misperception. Depression is one of the most consistent risk factors for predicting insomnia. Therefore, this study attempted to confirm the mediating effect of depression in exacerbating insomnia. @*Methods@#This study included 77 male and female aged 18–40 years who met diagnostic criteria for insomnia disorder based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Depression and insomnia severity were measured using self-report questionnaires, and actigraphy data were collected for 1 week. The sleep misperception index was calculated using the sleep diary and actigraphy. @*Results@#The Pearson correlation analysis was performed to examine the relationships between sleep misperception, insomnia, and depression. Sleep misperception was positively associated with depression (r=0.399, p<0.01). There was also a significant positive correlation between depression and insomnia severity (r=0.591, p<0.01). However, there was no significant correlation between sleep misperception and insomnia severity (r=0.210, p=0.07). Depression was found to have a full mediating effect on the relationship between sleep disturbance and severity of insomnia (n=77, B=6.1688, 95% confidence interval=2.9960, 10.4562). @*Conclusions@#This study verified the mediating effect of depression on the relationship between sleep misperception and insomnia severity. The results highlight the importance of considering depression and sleep misperception in insomnia treatment.