Impulsive adolescents exhibit inefficient processing and a low decision threshold when decoding facial expressions of emotions

Background Borderline personality disorder (BPD) is a debilitating psychiatric illness whose symptoms frequently emerge during adolescence. Critically, self-injury and suicide attempts in BPD are often precipitated by interpersonal discord. Initial studies in adults suggest that the interpersonal difficulties common in BPD may emerge from disrupted processing of socioemotional stimuli. Less is known about these processes in adolescents with BPD symptoms, despite substantial changes in socioemotional processing during this developmental period. Methods Eighty-six adolescents and young adults with and without BPD symptoms completed an emotional interference task involving the identification of a facial emotion expression in the presence of a conflicting or congruent emotion word. We used hierarchical drift diffusion modeling to index speed of processing and decision boundary. Using Bayesian multilevel regression, we characterized age-related differences in facial emotion processing. We examined whether BPD symptom dimensions were associated with alterations in facial emotion processing. To determine the specificity of our effects, we analyzed behavioral data from a corresponding nonemotional interference task. Results Emotion-related impulsivity, but not negative affectivity or interpersonal dysfunction, predicted inefficient processing when presented with conflicting negative emotional stimuli. Across both tasks, emotion-related impulsivity in adolescents, but not young adults, was further associated with a lower decision boundary - resulting in fast but inaccurate decisions. Conclusion Impulsive adolescents with BPD symptoms are prone to making errors when appraising facial emotion expressions, which may potentiate or worsen interpersonal conflicts. Our findings highlight the role of lower-level social cognitive processes in interpersonal difficulties among vulnerable youth during a sensitive developmental window.