0156 Subjective Sleepiness Across the Day in Patients with Sleep Disorders

Abstract Introduction According to the two-process model, sleep propensity rises during waking and it dissipates during sleep. However, the clinical assessment of subjective sleepiness usually overlooks changes of sleepiness across the day. A modified version of the Epworth sleepiness scale has been found to overcome this gap. With this instrument, an overall pattern of increasing sleepiness across the day has been reported. The aim of this study was to evaluate subjective sleepiness across the day in patients with sleep disorders. Methods Participants were recruited from the National Institute of Psychiatry. All patients who attended the sleep unit for the first time between December 2021 and November 2023 and filled the Time of Day Sleepiness Scale (ToDSS) were included. The ToDSS consists of 8 items of the Epworth sleepiness scale (ESS) but modified for gathering subjective perception of sleepiness in the morning, afternoon and evening. A general linear model with repeated measures was conducted to assess changes in sleepiness across the day. Results One hundred and ninety-five patients were included (female 68.4%, mean age 45.1 SD 15.3). All participants had at least one sleep disorder and 91.3% had a comorbid psychiatric disorder. Scores on ToDSS were: Morning 8.8 (SD=7.3) afternoon 10.6 (SD=6.9), evening 11.3 (SD=7.0); ESS=10.3 (SD=7.2). MANOVA showed a significant main effect for time (Pillai’s Trace 0.12; F=11.3, df 2,155, p.001). There were no significant effects for interactions time x sleep disorder x and time x sleep disorder x psychiatric morbidity. In contrast, a significant effect was found for time x psychiatric morbidity (Pillai’s Trace 0.17; F=2.0, df 14, 312, p.02). In participants with comorbid psychiatric disorders there was a significant increase in ToDSS from morning to afternoon (df 7, F=2.5, p=.01,) but not from afternoon to evening (df 7, F=2.0, p.05) Conclusion Discussion These results are in line with previous research which has described a pattern of increasing subjective sleepiness across the day. But they also suggest this pattern might be different in patients with psychiatric morbidity. Additional research to characterize the clinical implications of these findings is needed. Support (if any)