Acceptance and commitment therapy for nurses' sleep, rumination, psychological flexibility, and it's neural mechanism: A randomized controlled fNIRS study.

Given nurses often face sleep problems, this study compares two internet-delivered Acceptance and Commitment Therapy (ACT) interventions to improve sleep quality (SQ), psychological flexibility (PF), reduce rumination, and explore neural mechanisms. 477 nurses were randomly assigned to ACT linear psychotherapy model (LINEAR), ACT loop psychotherapy model (LOOP) and wait-list group. SQ, rumination, and PF were assessed with questionnaires. Prefrontal cortical activation changes were measured using functional near-infrared spectroscopy. The linear mixed-effects model demonstrated significant improvements in SQ, PF, and reduced rumination compared to pre-intervention for both models through enhanced psychological flexibility. LOOP showed a significantly superior effect compared to LINEAR. DLPFC activation increased following both interventions, with LOOP additionally stimulating the frontopolar area. Changes in the DLPFC mediated the relationship between intervention and outcome improvements. Frontopolar changes mediated SQ improvements but not rumination or PF. No significant changes in functional connectivity were observed during the verbal fluency task. Both interventions improved outcome variables, with LOOP being notably more effective, offering a novel approach. Mediation analyses highlight the role of DLPFC activation in understanding ACT's mechanisms and targeting insomnia treatment, while the mechanisms of LOOP's superior effect warrant further research. Chinese Clinical Trial Registry (ChiCTR2200063533). https://www.chictr.org.cn/.