A new study published in Psychological Medicine explores the relationship between brain reward sensitivity and the influence of delinquent peers on adolescents with disruptive behavior disorder. The research highlights how interactions between brain function and environmental factors may contribute to the severity of disruptive behaviors in adolescents.
Adolescents diagnosed with disruptive behavior disorders (DBD) exhibit a range of challenging behaviors including increased aggression, emotional instability, and risky decision-making. These behaviors have significant impacts on society, contributing to public health costs and affecting the individuals themselves, their victims, and their communities.
Despite the known issues associated with DBD, the underlying mechanisms that drive these behaviors are not fully understood. This gap in knowledge hampers the development of effective prevention and intervention strategies.
One prominent environmental factor linked to DBD is exposure to delinquent peers. Adolescents who associate with peers engaging in antisocial behavior are at higher risk of committing crimes and developing antisocial personality disorders later in life.
Previous studies suggest that the relationship between delinquent peer affiliation (DPA) and disruptive behavior could be due to two main processes: socialization effects, where delinquent peers influence the individual’s behavior, and selection effects, where individuals with a predisposition for disruptive behavior are more likely to choose delinquent peers. This study aims to examine these processes in greater detail by considering how the brain’s reward system may influence susceptibility to peer effects.
The study used data collected from a sample of adolescents with a history of disruptive behavior. Participants were originally part of a cohort of first-time offenders recruited in the Netherlands. For the current study, the researchers selected a subsample of these adolescents, focusing on those with a range of antisocial behaviors. The final sample included 126 adolescents, with the majority being male and around the age of 17.
The study measured the participants’ affiliation with delinquent peers using a self-report questionnaire that assessed both the level of peer delinquency and the degree of peer affiliation. The questionnaire provided a composite score indicating the extent of each participant’s association with delinquent peers.
To examine brain function, the researchers used functional magnetic resonance imaging (fMRI) while participants engaged in a monetary incentive delay (MID) task. This task involves participants responding to visual cues that signal the potential to win or lose money. The task is designed to activate the brain’s reward regions, particularly the ventral striatum (VS), amygdala, and medial prefrontal cortex (mPFC), which are known to be involved in reward processing.
The researchers analyzed changes in brain activity during the anticipation and outcome phases of the MID task. They then conducted multiple regression analyses to explore the interaction between delinquent peer affiliation, reward sensitivity (as measured by brain activity), and the severity of disruptive behavior symptoms.
The study found a significant positive correlation between delinquent peer affiliation and the severity of disruptive behavior disorder symptoms. However, there was no direct correlation between reward-related neural activity and either peer affiliation or disruptive behavior on its own.
Importantly, the researchers identified a significant interaction effect between peer affiliation and reward sensitivity in the ventral striatum during the outcome phase of the reward task. Adolescents who exhibited higher neural responsiveness to rewards in the ventral striatum showed a stronger association between delinquent peer affiliation and disruptive behavior symptoms. This suggests that adolescents with heightened reward sensitivity are more influenced by their delinquent peers in terms of developing disruptive behaviors.
The study also found that this interaction effect was more pronounced in younger adolescents and in males, indicating age and sex differences in how delinquent peer influences interact with brain function to affect behavior.
While the findings provide valuable insights, the study has several limitations. The sample was predominantly male, which limits the generalizability of the results to females. Another limitation is the cross-sectional design, which precludes conclusions about causality. Longitudinal studies tracking changes in brain function and behavior over time would be valuable in establishing causal relationships and understanding the developmental trajectory of these interactions.
The study, “The association between delinquent peer affiliation and disruptive behavior interacts with functional brain correlates of reward sensitivity: a biosocial interaction study in adolescent delinquents,” was authored by Jorim J. Tielbeek, Maarten van der Hooft, Moran D. Cohn, Peter M van de Ven, Tinca JC Polderman, Dick J Veltman, Danielle Posthuma, Carlo Schuengel, Lieke van Domburgh, and Arne Popma.