Poor Sleep Quality Diminishes Cognitive Functioning

Sufficient sleep is essential for optimum cognitive and psychological functioning. Diminished sleep quality is associated with depression and anxiety, but the extent to which poor sleep quality uniquely impacts attention and executive functions independent of the effects of the common underlying features of depression and anxiety requires further exploration. Here 67 healthy young adults were given the Minnesota Multiphasic Personality Inventory, second edition (MMPI-2), the Pittsburgh Sleep Quality Index (PSQI), and tests of attention and executive functions. Similar to findings from a previous study with healthy community-based older adults (Nebes, Buysse, Halligan, Houck, & Monk, 2009), participants who reported poor sleep quality on the PSQI endorsed significantly greater scores on MMPI-2 Restructured Clinical scales related to depression and anxiety (Cohen's d = 0.77–1.05). In addition, PSQI component scores indexing poor sleep quality, duration, and medication use were associated with diminished attention and executive functions, even after controlling for emotional reactivity or demoralization (rs = 0.21–0.27). These results add to the concurrent validity of the PSQI, and provide further evidence for subtle cognitive decrements related to insufficient sleep even in healthy young adults. Future extension of these findings is necessary with larger samples and clinical comparison groups, and using objective indices of sleep dysfunction such as polysomnography.