Longitudinal neurofunctional alterations following nonpharmacological treatments and the mediating role of regional homogeneity in subclinical depression comorbid with sleep disorders among college students.

Background: Clinical guidelines recommend nonpharmacological treatment (nPHT) as the primary intervention for subthreshold depression management. Counseling (CS) and electroacupuncture (EA) are two promising nonpharmacological approaches for improving both depression and sleep disturbance. However, the intrinsic neuroimaging mechanisms underlying the antidepressant effects of these nPHTs are not yet fully understood.

Methods: We analyzed longitudinal resting-state functional magnetic resonance imaging (rs-fMRI) data from a randomized, single-blind clinical trial involving 96 first-episode, drug-naïve college students with subclinical depression and sleep disorders (sDSD; mean age 20.43 ± 2.72 years; 66.7% female) and 90 healthy controls (HCs; mean age 21.02 ± 2.68 years; 61.1% female). Participants with sDSD were randomly assigned to receive either scalp EA (n = 47) or CS (n = 49) for six weeks. The regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) before and after nPHT were calculated. Correlation and mediation analyses were performed to investigate the complex relationships between fMRI indicators and clinical symptoms.

Results: The ALFF in the left paracentral lobule in sDSD patients presented an interaction effect between group and time following six weeks of nPHT. In the CS group, the ALFF in the left paracentral lobule decreased (p < 0.001), and in the EA group, it increased (p < 0.05). Compared with HCs, the baseline sDSD has many abnormal brain regions in terms of ALFF and ReHo. The whole-brain average ReHo was negatively correlated with depression scores (r = -0.26, p < 0.001) and sleep quality scores (r = -0.25, p < 0.001) and mediated the association between depression and sleep disorders [β = 0.2857, p < 0.001, 95% CI (0.23, 0.35)].

Conclusions: Nonpharmacological therapies provide different therapeutic outcomes in terms of the same rs-fMRI indicator. ALFF in the left paracentral lobule could be used as an imaging biomarker in nPHT selection. Rs-fMRI indicators are promising for understanding the neural basis of the complex relationship between subclinical depression and insomnia comorbidities in young adults.