Dynamicity of brain network organization and their community architecture as characterizing features for classification of common mental disorders from the whole-brain connectome

The urgency of addressing common mental disorders (bipolar disorder, ADHD, and schizophrenia) arises from their significant societal impact. Developing strategies to support psychiatrists is crucial. Previous studies focused on the relationship between these disorders and changes in the resting-state functional connectome’s modularity, often using static functional connectivity (sFC) estimation. However, understanding the dynamic reconfiguration of resting-state brain networks with rich temporal structure is essential for comprehending neural activity and addressing mental health disorders. This study proposes an unsupervised approach combining spatial and temporal characterization of brain networks to classify common mental disorders using fMRI timeseries data from two cohorts (N=408 participants). We employ the weighted stochastic block model to uncover mesoscale community architecture differences, providing insights into neural organization. Our approach overcomes sFC limitations and biases in community detection algorithms by modelling the functional connectome’s temporal dynamics as a landscape, quantifying temporal stability at whole-brain and network levels. Findings reveal individuals with schizophrenia exhibit less assortative community structure and participate in multiple motif classes, indicating less specialized neural organization. Patients with schizophrenia and ADHD demonstrate significantly reduced temporal stability compared to healthy controls. This study offers insights into functional connectivity (FC) patterns’ spatiotemporal organization and their alterations in common mental disorders, highlighting the potential of temporal stability as a biomarker. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement AB acknowledges the generous support of the NBRC Flagship program BT/ MEDIII/ NBRC/ Flagship/ Program/ 2019: Comparative mapping of common mental disorders (CMD) over lifespan. We acknowledge the generous support of NBRC Core funds and the Computing facility. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: We downloaded resting state functional magnetic resonance imaging (fMRI) data from 285 participants who participated in the University of California Los Angeles (UCLA) Consortium for Neuropsychiatric Phenomics LA5c study. The public database was obtained via openfMRI (https://openfmri.org/dataset/ds000030/) A publicly available dataset from the centre for Biomedical Research Excellence (COBRE) was obtained obtained through the International Neuroimaging Data-sharing initiative (http://fcon_1000.projects.nitrc.org/indi/retro/cobre.html). This was originally released under Creative Commons Attribution Non-Commercial. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors * ADHD : Attention-Deficit Hyperactivity Disorder FC : Functional connectivity dFC : Dynamic functional connectivity WSBM : Weighted stochastic block model PCA : Principal component analysis SZ : Schizophrenia BP : Bipolar disorder EPI : Echo-planar imaging SCID : Structured Clinical interview used for DSM disorders BOLD : Blood oxygen level dependant TS : Temporal stability RSN : Resting state network