Disrupted global and local brain functional network dynamics in adolescents with obsessive-compulsive disorder

BACKGROUND: Obsessive-compulsive disorder (OCD) frequently emerges during adolescence, a critical period for the development of static and dynamic properties of large-scale brain networks. Although previous studies have reported altered static connectivity in adolescents with OCD, the temporal organization of functional networks during this stage remains largely unexplored. METHODS: We analyzed resting-state fMRI data from 40 adolescents with OCD and 40 age- and sex-matched healthy controls. Group independent component analysis (ICA) was used to identify intrinsic connectivity networks (ICNs). A sliding-window approach and k-means clustering were applied to derive dynamic brain states, while graph-theoretical metrics (strength, local efficiency, clustering coefficient) were computed to assess nodal variability over time. Group comparisons were performed using general linear models controlling for age and sex, and symptom correlations were tested using partial correlation analyses. RESULTS: Compared to controls, OCD patients spent significantly less time in a globally integrated brain state characterized by strong intra- and inter-network connectivity. At the local level, reduced temporal variability was observed in the striatum, thalamus, and dorsolateral prefrontal cortex, key nodes of the cortico-striato-thalamo-cortical (CSTC) circuit. Notably, reduced striatal variability correlated with greater OCD symptom severity and decreased time in the integrated brain state. CONCLUSIONS: These findings reveal disrupted dynamic network integration and reduced functional flexibility in adolescents with OCD, both globally and locally. This multilayered impairment may reflect early pathophysiological mechanisms and offers potential targets for age-sensitive neuromodulation strategies. CLINICAL TRIAL REGISTRATION: ChiCTR2400092275, Chinese Clinical Trial Registry (www.chictr.org.cn).