Suicidal risk is associated with hyper-connections in the frontal-parietal network in patients with depression.

Suicide is a complex behavior strongly associated with depression. Despite extensive research, an objective biomarker for evaluating suicide risk precisely and timely is still lacking. Using the precision resting-state fMRI method, we studied 61 depressive patients with suicide ideation (SI) or suicide attempt (SA), and 35 patients without SI to explore functional biomarkers of suicide risk. Among them, 21 participants also completed electroconvulsive therapy (ECT) treatment, allowing the examination of functional changes across different risk states within the same individual. Functional networks were localized in each subject using resting-state fMRI and then an individualized connectome was constructed to represent the subject's functional brain organization. We identified a set of connections that track suicide risk (r = 0.41, p = 0.001) and found that these risk-associated connections were hyper-connected in the frontoparietal network (FPN, p = 0.008, Cohen's d = 0.58) in patients with suicide risk compared to those without. Moreover, ECT treatment significantly reduced (p = 0.001, Cohen's d = 0.56) and normalized these FPN hyper-connections. These findings suggest that connections involving FPN may constitute an important biomarker for evaluating suicide risk and may provide potential targets for interventions such as non-invasive brain stimulation.