0715 Impact of Depression Severity in Idiopathic Hypersomnia and Hypersomnia Associated with a Psychiatric Disorder

Abstract Introduction Sleep disorders are often associated with psychiatric disorders, and hypersomnolence and depression commonly co-occur. Depression can also be a consequence of central disorders of hypersomnolence such as Idiopathic Hypersomnia (IH). Since IH and depression have overlapping symptoms, this can complicate accurate diagnosis and treatment planning. Therefore, we aimed to examine the relationship between depression-related traits and sleep metrics in both Idiopathic Hypersomnia (IH) and Hypersomnia Associated with a Psychiatric Disorder (HAPD). Methods As part of the study, participants completed a clinical interview and questionnaires about sleep and mood to determine eligibility and be placed into one of the two groups: IH or HAPD. Subjects wore a GENEActiv watch to measure movement and light and simultaneously completed sleep diaries. Participants completed two overnight polysomnograms (PSG), with the second night followed by a standard Multiple Sleep Latency Test (MSLT). Questionnaire and PSG measures were compared between groups using two-sample t-tests. Pearson correlations were used to examine the relationship between each measure and depression severity. Results Thirty participants completed questionnaires and at least one night of polysomnography. There was a total of n=12 for IH and n=18 for HAPD. The average age was 29.9 years, 83.3% female, and 86.2% Caucasian. There were no significant differences between groups on mood or sleep measures. There was a positive correlation between Hypersomnia Severity Index and depression severity (r= 0.375, p= 0.041), and a positive correlation between sleep latency and depression severity (r= 514, p= 0.021). Conclusion These data demonstrate the significant overlap in symptomology and thus suggest that there might be difficulty in differentiating between IH and HAPD. Depression severity across groups, rather than IH or HAPD, may be a stronger predictor of sleep and hypersomnolence measures. More in-depth depressive measures may provide further insight than self-reported depression symptoms. Support (if any) Jazz Pharmaceuticals