Abnormal regional homogeneity in young adult suicide attempters with no diagnosable psychiatric disorder: A resting state functional magnetic imaging study

• We used resting state fMRI to explore changes in neural circuit organization associated with suicidal behavior in young adults.
• Local functional connectivity is altered in multiple regions of the cerebral cortex, limbic system, and cerebellum of suicidal young adults.
• Suicide attempters also had significantly higher total Barratt Impulsiveness Scale scores compared with healthy controls.
• Resting state fMRI studies may clarify the pathophysiological mechanisms of suicidal behavior and assist in identifying high-risk individuals.

Many young adults who attempt suicide have no discernible mental illness, suggesting an etiology distinct from other psychiatric disorders. Neurological anomalies associated with a history of suicidal behavior may predict future risk. In the present study, we explored changes in neural circuit organization associated with suicidal behavior by comparing local synchronization of resting-state functional magnetic resonance imaging signals in suicide attempters without a psychiatric diagnosis (SA group, 19.84±1.61 years, n=19) with those in healthy controls (HC group, 20.30±1.72 years, n=20) using regional homogeneity (ReHo) analysis. The SA group exhibited significantly lower mean ReHo in the left (L) fusiform and supraorbital inferior frontal gyri, L hippocampus, bilateral parahippocampal and middle frontal gyri, right (R) angular gyrus, and cerebellar lobules RVIII, RII, and LVI compared with the HC group. Conversely, in the SA group, ReHo was higher in the R supraorbital middle frontal gyrus, R inferior parietal lobe, and L precuneus. The SA group also had significantly higher total Barratt Impulsiveness Scale scores compared with the HC group. Local functional connectivity is altered in multiple regions of the cerebral cortex, limbic system, and cerebellum of suicidal young adults. Elucidating the functional deficits associated with these ReHo changes may clarify the pathophysiological mechanisms of suicidal behavior and assist in identifying high-risk individuals.