0075 Melatonin impairs morning cognition in healthy young adults without any benefit to sleep

Abstract Introduction Exogenous melatonin has been shown to improve sleep in individuals with disorders, such as insomnia and delayed phase disorder. However, research on the effect of exogenous healthy young adults is limited. Additionally, there some evidence that can negatively affect cognitive processes, long-term memory, working attention. Therefore, we assessed supplementation nocturnal morning cognition undergraduates. Methods In evening, participants (N = 120) completed three tasks: Psychomotor Vigilance Task (PVT; a measure attention), UNRAVEL (a procedural placekeeping), Paired Associates Learning (PAL) test memory). We then asked take pill under double-blind conditions contained either or placebo. Afterwards, received an 8-hour opportunity monitored polysomnography (PSG). One hour after waking, PAL, UNRAVEL, PVT again. Results compared performance across placebo conditions, evening covariate. Interestingly, had more placekeeping errors than did not PAL performance. found no significant differences between groups any our measures. Conclusion The results suggest negative effects may outweigh benefits for adults, particularly when measured shortly opportunity. Our also factors captured by PSG accurately predict next-day performance, researchers should consider additional factors, concentration, assessing relationship Support (if any) This work was funded Office Naval Research (N00014-20-1-2739).