Characterising the inconsistency between perceived and actual sleep and its impact upon cognition and mood

Sleep profoundly influences human behaviour across cognition, affect, and daily experience. This study evaluated how subjective reports and objective measures of sleep capture the interaction between sleep quality and quantity on cognition and affect. We collected subjective sleep reports using the Pittsburgh Sleep Quality Index and objective seven-day actigraphy recordings from 83 participants. A test battery, including the Stop Signal, Digit Span, and Emotional Bias Tasks, measured response inhibition, working memory, and affect. Mood was evaluated using the Positive and Negative Affect Schedule, State-Trait Anxiety Inventory, and Beck's Anxiety Inventory. We reveal that subjective sleep reports do not predict objectively measured sleep duration or quality. We demonstrate that objective measures predict cognitive performance on executive function and memory tasks for the upper and lower sleep quartiles, while subjective reports do not. Moreover, we demonstrate that subjective reports, but not objective measures, are strongly predicted by emotional state. These findings suggest that while subjective measures do not accurately index actual sleep, they are a reliable proxy for emotional well-being. We propose that combined subjective and objective measures are required to characterise the multifaceted interaction between sleep, cognition and emotion. We discuss the implications of these findings for understanding the cause-effect relationship of sleep-disturbance in neurological and psychiatric disorders.