0899 Impaired Neurobehavioral Alertness Quantified by the Psychomotor Vigilance Task is Associated with Depression in the Wisconsin Sleep Cohort Study

Abstract

Introduction: Hypersomnolence plays an important role in the presentation and course of mood disorders. Standard objective measures of daytime sleep propensity are of little to no value in predicting depressive illness. This study examined the psychomotor vigilance task (PVT), an objective measure of neurobehavioral alertness, and its cross-sectional and longitudinal associations with depressive symptomatology in the Wisconsin Sleep Cohort (WSC) Study. Method(s): The sample consisted of 1547 separate 10-minute PVT assessments conducted in 932 unique individuals participating in the WSC. Cross-sectional and longitudinal conditional logistic regression models were used to estimate associations between the primary outcome of depression (adjusted Zung scale>=50) and six separate PVT variables: mean reciprocal reaction time (1/RT); total lapses (RTs>=500msec; LAPSE); total false responses (FALSE); reciprocal of the mean of the 10% fastest (FAST) and 10% slowest (SLOW) RTs; and slope of the linear regression line for all transformed 1/RTs (SLOPE). Covariates included age, sex, BMI, chronic medical conditions, antidepressant use, sedative hypnotic medication use, caffeine use, tobacco use, alcohol use, sleep-disordered breathing, and habitual sleep duration. Result(s): In fully-adjusted cross-sectional models, 1/RT, LAPSE, FAST, and SLOW were each significantly (all p<0.0001) associated with depression, such that worse neurobehavioral alertness was associated with increased odds of depressive symptomatology. Similar, though attenuated, findings were observed utilizing conditional longitudinal models that examined changes in depression status in the subset of participants with repeated PVT assessments. FALSE and SLOPE were not associated with depression in either cross-sectional or conditional longitudinal models. Conclusion(s): These findings suggest components of the PVT, an objective measure of neurobehavioral alertness, are significantly associated with depressive symptomatology. Further research is indicated to clarify the role of the PVT in the assessment of hypersomnolence in mood disorders.