Neural correlates of affective theory of mind in medication-free nonsuicidal self-injury: An fMRI study

Emerging evidence indicates that emotion processing deficits are associated with nonsuicidal self-injury (NSSI). However, limited attention has been paid to the socio-affective functions of NSSI. In this study, we aimed to investigate the affective theory of mind (ToM) in medication-free individuals engaging in NSSI at both behavioral and neural levels. Twenty-eight individuals (mean age = 22.96 years) who engaged in NSSI and 38 age-, sex-, and IQ-matched controls (mean age = 22.79 years) underwent functional magnetic resonance imaging while performing the Reading the Mind in the Eyes Test (RMET). All participants also completed the Difficulties in Emotion Regulation Scale (DERS), Toronto Alexithymia Scale (TAS-20), and Beck Scale for Suicide Ideation (BSI). Although we did not find significant group differences in the RMET performance, the NSSI group, relative to the controls, exhibited significantly greater left medial superior frontal lobe activation and decreased right angular gyrus activation than did the control group. Reduced right angular gyrus activity was related to higher DERS and TAS scores across all participants. Our findings provide new evidence for aberrant neural processing of affective ToM in self-injurers. Future studies in developing intervention protocols for NSSI should focus on the multifaceted phases of socio-affective processing.

Automated summary

Emerging evidence suggests that individuals who engage in nonsuicidal self-injury (NSSI) may have deficits in emotion processing. However, little attention has been given to the socio-affective functions of NSSI. In this study, researchers aimed to investigate the affective theory of mind (ToM) in medication-free individuals with NSSI at both behavioral and neural levels. The results showed that although there were no significant differences in performance on the Reading the Mind in the Eyes Test (RMET), the NSSI group exhibited different brain activation patterns compared to the control group, with increased activation in the left medial superior frontal lobe and decreased activation in the right angular gyrus. Reduced activation in the right angular gyrus was associated with higher scores on difficulties in emotion regulation and alexithymia. These findings provide new evidence for abnormal neural processing of affective ToM in self-injurers.