Neurofunctional Correlates of Hostility in Adolescents With Externalizing Disorders: Implications for Clinical Assessment and Intervention.

Introduction: Previous neuroimaging studies have rarely investigated hostility as a distinct cognitive-emotional dimension of aggression. Most research has focused on overall aggressive behavior without differentiating hostility from other behavioral components. Specifically, the neural correlates associated with hostility in adolescents diagnosed with externalizing disorders have not been thoroughly investigated. To fill this void, the current research focused on hostility- a fundamental psychological element of violence-and its neurofunctional foundations in adolescents. Methods: This study examined resting-state functional connectivity (rsFC) differences in adolescents with high and low hostility, focusing on brain networks related to emotion regulation, salience, and executive control using the Buss-Perry aggression questionnaire (BPAQ) scale. We utilized seed-to-Voxel and region of interest (ROI)-to-ROI functional magnetic resonance imaging (fMRI) models to examine rsFC in two groups of adolescents: 14 with externalizing disorders and 13 typically developing controls. Results: Seed-to-Voxel analysis showed greater rsFC in low-hostility adolescents within two clusters: Left dorsolateral prefrontal cortex (dlPFC) (BA 9/46) and ventromedial prefrontal cortex (vmPFC) (BA 10/11) compared to high-hostility peers. Both target regions represent top-down emotional processing and social-affective processing, respectively, providing evidence that the lower hostility group is more efficient at regulating aggressive impulses. ROI-to-ROI analysis revealed significantly reduced connectivity in high-hostility adolescents, particularly between the dlPFC and the amygdala, and between the frontal midline and the amygdala, indicating impaired emotion regulation. Lowered links were also found between dorsal attention and salience networks, visual-limbic regions, and between cerebellar and medial prefrontal areas. Conclusion: These differences reinforce disrupted functioning of conceptually relevant executive and attentional networks, as well as affective and socioemotional networks in adolescents with increased hostility. We perceive these findings collectively as a neurobiological contrast between low and high hostility, and note that decreased connectivity of both the prefrontal and salience networks may represent targets for neurotherapeutic interventions to reduce aggression in children and adolescents with externalizing problems. Highlights: The study aimed to examine the neural basis of hostility in adolescents with externalizing disorders using rs fMRI and network level connectivity analysis.High hostility adolescents showed reduced functional connectivity in salience, attentional, and prefrontal-limbic networks, reflecting poor emotional salience detection and control.Weak coupling between dlPFC/vmPFC and amygdala indicated impaired top down emotion regulation and heightened reactive aggression.Findings revealed altered cerebello prefrontal communication, highlighting the cerebellum's extended role in affective processing beyond motor control.The distinct rsFC patterns may serve as biomarkers for early detection and intervention targeting emotional dysregulation in hostile or aggressive youth. Plain Language Summary: This study explored the neural mechanisms underlying hostility in adolescents with externalizing disorders using resting state functional magnetic resonance imaging (rs fMRI). Whereas most previous research has treated hostility as part of general aggression, this work examined it as a distinct cognitive emotional construct characterized by mistrust, cynicism, and antagonism toward others. The goal was to determine how patterns of functional connectivity (rsFC) differ between adolescents exhibiting high and low levels of hostility. Analyses revealed that adolescents with high hostility scores showed reduced connectivity across several key brain networks that coordinate emotional and attentional control. In particular, functional links within the salience network, dorsal attention network, visual limbic system, and cerebello prefrontal circuits were significantly weaker. Such disruptions suggest inefficient processing of salient environmental cues and difficulty mobilizing regulatory mechanisms during emotionally charged or ambiguous situations. In contrast, adolescents characterized by low hostility displayed stronger intra and inter network connectivity within prefrontal control regions, notably the dorsolateral prefrontal cortex (dlPFC) and ventromedial prefrontal cortex (vmPFC). Enhanced connectivity in these areas indicates more efficient top down control over emotional and behavioral responses. Importantly, weakened coupling between the prefrontal cortex and amygdala was observed in high hostility individuals, implying ineffective regulation of subcortical emotional reactivity. Additional findings included disrupted communication in the salience network (encompassing the insula, anterior cingulate cortex, and supramarginal gyrus) and altered cerebello prefrontal links, underscoring the cerebellum's underrecognized role in emotional regulation. Overall, the findings support a network based model of hostility, in line with theories like the I³ model of aggression, highlighting that hostility stems from dysfunctional integration among attention, salience, and inhibitory control systems. The study concludes that altered brain network organization may serve as a neural risk marker for developing aggressive or antisocial behaviors in adolescence.