Stress and sleep: Novel insights into stress-related sleep disorders from EEG features to neural circuitry.

Sleep disorders and stress-related psychiatric conditions exhibit a high degree of comorbidity. Epidemiological patterns suggest that sleep disturbances frequently precede the onset of affective symptoms. This temporal relationship indicates that stress-induced disruption of sleep physiology may act as an early driver in the pathogenesis of psychiatric disorders. Current clinical assessments relying on subjective measures or standard polysomnography staging may overlook subtle neurophysiological alterations. This review examines the impact of stress on sleep dynamics through the lens of specific electroencephalographic (EEG) features including sleep spindles and slow-wave activity as well as rapid eye movement (REM) theta rhythms. We integrate findings from human and animal studies to elucidate how acute and chronic stress differentially remodel these oscillatory patterns. The analysis extends to the underlying neural circuitry. It explores how dysregulation in stress-responsive systems such as the hypothalamic-pituitary-adrenal (HPA) axis and locus coeruleus-norepinephrine (LC-NE) system interacts with sleep-wake regulatory networks to compromise sleep homeostasis and emotional memory processing. Evidence suggests that the decoupling of oscillatory events like the slow oscillation-spindle complex may represent a core mechanism linking stress to maladaptive emotional regulation. Furthermore, we evaluate the potential of these EEG signatures to serve as objective biomarkers for disorders including post-traumatic stress disorder (PTSD) and major depressive disorder (MDD). The review concludes by discussing translational implications. This includes the prospect of targeting specific neural oscillations through pharmacological or neuromodulatory interventions to restore sleep integrity and mitigate psychiatric risks.