Anterior insula reactivity to loss moderates the association between trait impulsivity and future suicidal ideation...

While impulsivity is a prominent risk factor for adolescent suicidal thoughts and behaviors (STB), impulsivity specifically following negative experiences shows more consistent associations. Individual differences in neural sensitivity to negative outcomes may explain why some impulsive adolescents develop STB while others do not. We examined whether neural reactivity to monetary loss moderates the relationship between impulsivity and future suicidal ideation (SI). Sixty-three adolescents (ages 13-18 at baseline; 59% female) with varying familial risk for psychopathology completed impulsivity measures and an fMRI monetary win/loss paradigm at baseline, and SI assessment one year later. Moderation analyses tested whether BOLD signal extracted from significant clusters (p_FWE <.05) within an a priori anatomical mask moderated the association between impulsivity and future SI. Right anterior insula (aINS) activation to monetary loss moderated the association between impulsivity and future SI (B =.017, p < .01). Adolescents with high impulsivity showed elevated future SI when aINS response to loss was high, but lower future SI when aINS response was low. Effects persisted after controlling for depression and anhedonia severity. Johnson-Neyman analyses revealed a crossover interaction pattern, with impulsivity-SI associations at both high and low aINS activation levels. Higher sensitivity to negative outcomes in neural salience processing regions could serve as a vulnerability context for pathways from trait impulsivity to SI. These findings support integrating neurodevelopmental perspectives into suicide risk models and suggest that neural response patterns during adolescence may help identify which impulsive youth are more likely to develop SI.