Which cognitive emotion-regulation strategies are implicated in the association between sleep quality and negative affect?

Poor sleep is causally related to the experience of mental health difficulties, and improving sleep can also improve mental health, positioning sleep as an important transdiagnostic treatment target in mental healthcare. However, considerably less is known about the psychological processes through which sleep may influence mental health. Identifying these processes could refine theoretical understanding and reveal specific targets for interventions. This large preregistered cross-sectional study examined cognitive emotion regulation as a candidate mechanism. A total of 899 adults completed measures of sleep quality, cognitive emotion regulation and negative affect. Parallel mediation models examined indirect associations through adaptive and maladaptive regulation and nine specific strategies. The analyses indicated that poorer sleep quality was associated with greater negative affect (β = 0.51, 95% CI = 0.46 to 0.56). Indirect associations were observed through maladaptive regulation (β = 0.15, 95% CI = 0.12 to 0.18) and adaptive regulation (β = 0.02, 95% CI = 0.01 to 0.04). When all nine strategies were modelled simultaneously, indirect associations were observed through self-blame (β = 0.07), rumination (β = 0.05), catastrophising (β = 0.04) and refocusing on planning (β = 0.03). Cognitive emotion regulation therefore represents a plausible psychological process linking sleep quality with negative affect, particularly through maladaptive strategies. Self-blame, rumination and catastrophising provide specific, theoretically coherent priorities for future research. Nevertheless, the cross-sectional design cannot establish temporal ordering or causality. Longitudinal and experimental studies are now required to test whether poor sleep changes the use of these strategies, whether they subsequently influence negative affect, and whether modifying them improves the mental-health benefits of sleep interventions.