Altered Interpersonal Neural Synchronization During Social Interaction After Shared Excluded Experiences in Adolescents With Depression.

Background: Major depressive disorder (MDD) is common in adolescents, and adolescents' brains develop intensively but are still immature, making them more vulnerable during social interaction when exposed to public psychosocial stressors. Thus, it is essential to examine how a shared psychosocial stressor, i.e., shared excluded experiences, influences social interaction in adolescents with depression. Methods: We designed a 4-player Cyberball game involving 2 virtual players and 2 real players and recruited 34 dyads of healthy adolescents and 34 dyads of adolescents with depression. This allowed us to investigate the responses of adolescents with depression to shared excluded experiences and explore the underlying interpersonal neural synchronization (INS), which can indicate mutual empathy, with functional near-infrared spectroscopy. Results: We found that shared excluded experiences enhanced adolescents' social interaction but decreased INS between paired excluded adolescents. Such discrepancy suggested reduced mutual empathy between the excluded adolescents despite their increased interaction after shared exclusion. No significant between-group differences were observed in behavioral responses to shared excluded experiences. Subsequent analyses revealed that adolescents with MDD experienced more negative feelings compared with healthy control participants (HCs), and they demonstrated stronger INS than HCs after shared exclusion, which collectively indicate higher empathic stress in adolescents with depression. In addition, there were altered brain-behavioral association patterns in responses to shared excluded experiences in adolescents with depression. Conclusions: Our study gives us deeper insights into how a shared psychosocial stressor impacts INS in adolescents with depression, and it suggests that INS could be more sensitive than behavioral responses at detecting social interaction deficits in adolescents with depression.