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Background: Physical inactivity exacerbates poorer sleep quality, but potential underlying mechanisms of this association remain unknown. The present study aims to disentangle the pathways linking psychical activity to sleep quality through the serial mediation effect of anxiety and depression in a Chinese population., Methods: Data analyzed were from Guangdong Sleep and Psychosomatic Health Survey, a cross-sectional population-based study with a representative sample of adult inhabitants aged 18-85 years living in Guangdong province, China. A total of 13,768 participants were included with the response rate of 80.4%. Singe and serial mediation analyses were conducted to examine whether anxiety and depression mediated the relationship between physical activity and sleep quality, independently and jointly., Results: Both direct and indirect effects of physical activity on sleep quality were found. As predicted, anxiety and depression mediated the relationship between physical activity and sleep quality (B Anxiety  = -0.17, 95% bootstrap CI: -0.20 to -0.15; B Depression = -0.25, 95% bootstrap CI: -0.28 to -0.21), respectively. In addition, serial mediation analyses indicated that the association of physical activity and sleep quality is mediated by anxiety and depression in a sequential manner (B = -0.13, 95% bootstrap CI: -0.15 to -0.11)., Limitations: The primary limitation of the study is the cross-sectional design, which limits the causal inference ability., Conclusions: These findings highlight the role of anxiety and depression as serial mediators of the relationship between physical activity and sleep quality. Thus, exercise-based programs focusing on improving sleep could benefit from a multi-faceted approach therapeutically targeting psychiatric disorders., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Neuroimaging studies suggest that the prefrontal cortex (PFC) is involved in the pathophysiology of major depression. Repetitive transcranial magnetic stimulation (rTMS) as an antidepressant intervention has increasingly been investigated in the last two decades. In this study metabolic changes within PFC of severely depressed patients before and after rTMS were evaluated by proton magnetic resonance spectroscopy (1H-MRS)., Method: Thirty-four young depressed patients with treatment-resistant unipolar depression were enrolled in a double-blind, randomized study active ((n=19) vs. sham(n=15)), and the PFC was investigated before and after high-frequency (15 Hz) rTMS using 3-tesla proton magnetic resonance spectroscopy. Response was defined as a 50% reduction of the Hamilton depression rating scale. The results were compared with 28 age- and gender-matched healthy controls., Results: In depressive patients a significant reduction in myo-inositol (m-Ino) was observed pre-rTMS (p<0.001). After successful treatment, m-Ino increased significantly in left PFC and the levels no longer differed from those of age-matched controls. In addition to a positive correlation between clinical improvement and an increment in m-Ino ratio, a correlation between clinical improvement and early age onset was observed., Conclusions: Our results support the notion that major depressive disorder is accompanied by state-dependent metabolic alterations, especially in myo-inositol metabolism, which can be partly reversed by successful rTMS., (Copyright © 2010 Elsevier Inc. All rights reserved.)