The relationship between sleep, mental health, and performance on tests of pattern separation in young adults

Study objectives: Young adults experience the highest rates of mental health disorders of any age group. Depression and anxiety symptoms are often associated with both sleep disturbances and cognitive impairments. Here, we investigated whether the effects of sleep moderate the effects of depression and anxiety on cognitive performance. We were particularly interested in cognitive tasks designed to tax pattern separation, which we hypothesize are most sensitive to the cognitive impairments caused by mental health symptoms and sleep disturbances. Methods: We recruited young adults (N=89; aged 18-30 years) and remotely monitored their sleep for 7 consecutive days using wrist actigraphy and daily sleep diaries. On day 7, participants completed in-person cognitive testing and mental health questionnaires. Cognitive tests included the Psychomotor Vigilance Task (PVT), Cambridge Neuropsychological Test Automated Battery (CANTAB), and the Mnemonic Similarity Task (MST). The CANTAB Delayed Matching to Sample (DMS) and the MST, are designed to tax pattern separation. Mental health questionnaires included Becks Depression Inventory (BDI) and Becks Anxiety Inventory (BAI). Results: Eighty participants (mean age: 20.13, SD: 2.00) were included in the final analyses. Depressive symptoms were significantly correlated with performance on the PVT and CANTAB DMS. Bedtime and wake-up times were significantly correlated with performance on DMS and MST. Conclusion: Young adults experiencing depressive symptoms tend to have later wake-up times. Sleep timing and mental health independently affect performance on tests of pattern separation. Understanding the relationship between mental health, sleep, and cognitive performance is important for designing interventions to promote well-being in young adults.