Sleep and mental health independently affect cognitive performance in university students

Abstract

ObjectivesYoung adults experience the highest rates of mental health disorders of any age group. Given that mental health disorders are associated with sleep disturbances and cognitive impairments, we investigated whether sleep moderates the effects on cognition. MethodsUniversity students (N=89; aged 18-30 years) remotely monitored their sleep for seven consecutive days using wrist actigraphy and sleep diaries. On day seven, participants completed 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). CANTABs Delayed Matching to Sample (DMS) and MST are designed to tax pattern separation, a computational mechanism supporting encoding of similar experiences as distinct representations. Becks Depression Inventory and Becks Anxiety Inventory assessed mental health. ResultsEighty participants (mean age: 20.13{+/-}2.00) were included in the analyses. Most participants reported mild to severe depressive and anxiety symptoms. Depressive symptoms were correlated with wake-up time ({rho}=.35, p=.002) as well as PVT ({rho}=.26, p=.02) and DMS ({rho}=.24, p=.04) performance. Bedtime was correlated with performance on MST (r=-.29, r=.02) and DMS ({rho}=.25, p=.03), while wake-up time was correlated with performance on MST (r=- .31, p=.01) and DMS ({rho}=.28, p=.01). Sleep did not moderate the effects of mental health on cognitive performance. ConclusionCognitive tests taxing pattern separation are sensitive to depressive symptoms and sleep timing. While students face a disproportionate burden of mental health disorders compromising cognitive functioning, improving sleep quality may offer a partial, though not moderating, pathway to alleviating these cognitive impairments.