The present study examined longitudinal trajectory classes and correlates of triarchic psychopathy domains (boldness, meanness, and disinhibition) from age 16 to 22, leveraging Multidimensional Personality Questionnaire (MPQ)-based triarchic scales data gathered on a large community sample (ns ranging between 483 and 775 across waves) oversampled for parental substance use disorder (SUD). Growth mixture models were conducted to examine longitudinal trajectory classes for each domain, and their associations with environmental covariates (e.g., neighborhood disadvantage and parental SUD) and outcomes at age 22 (e.g., violent behavior, antisocial personality disorder, and an overall problem index capturing internalizing symptoms and social problems). For boldness, all participants fell in the same class showing relative stability over time. Comparable solutions were recovered for meanness and disinhibition (high-stable/increasing, mid-range decreasing, and low-decreasing). Links with external correlates supported well-known differences between boldness and both meanness and disinhibition and additionally revealed interesting differences between meanness and disinhibition, suggesting that environmental covariates better discriminated meanness trajectory classes. These results demonstrate considerable developmental heterogeneity in these traits across adolescence into young adulthood, which relates to outcomes associated with antisociality and general life struggles. Further, these findings support the adequacy of the MPQ as an operationalization tool for longitudinal investigations on psychopathy.

Attention-deficit/hyperactivity disorder (ADHD) symptoms are associated with myriad adverse outcomes, including interpersonal difficulties, but factors that moderate the developmental course and functional impact of ADHD over time are not well understood. The present study evaluated developmental contributions of the triarchic neurobehavioral traits (boldness, meanness, and disinhibition) to ADHD symptomatology and its subdimensions from adolescence to young adulthood. Participants were twins and triplets assessed at ages 14, 17, and 19 (initial N = 1,185, 51.2% female). Path analyses using negative binomial regression revealed that boldness at age 14 was associated with more ADHD symptoms cross-sectionally (especially hyperactivity/impulsivity), but fewer symptoms (especially inattention) at age 19 in the prospective analysis. Notably, inclusion of interpersonal problems at ages 14 and 17 as covariates reduced the latter effect to nonsignificant. Disinhibition concurrently and prospectively predicted higher levels of ADHD symptoms, including both subdimensions, and the prospective effects were partially mediated by greater social impairment at age 17. Meanness prospectively (but not concurrently) predicted higher levels of hyperactivity/impulsivity symptoms. Sex moderated certain associations of meanness and disinhibition with ADHD symptoms. These findings highlight how fundamental neurobehavioral traits shape both psychopathology and adaptive outcomes in the developmental course of ADHD.

The triarchic model was advanced as an integrative, trait-based framework for investigating psychopathy using different assessment methods and across developmental periods. Recent research has shown that the triarchic traits of boldness, meanness, and disinhibition can be operationalized effectively in youth, but longitudinal research is needed to realize the model's potential to advance developmental understanding of psychopathy. We report on the creation and validation of scale measures of the triarchic traits using questionnaire items available in the University of Southern California Risk Factors for Antisocial Behavior (RFAB) project, a large-scale longitudinal study of the development of antisocial behavior that includes measures from multiple modalities (self-report, informant rating, clinical-diagnostic, task-behavioral, physiological). Using a construct-rating and psychometric refinement approach, we developed triarchic scales that showed acceptable reliability, expected intercorrelations, and good temporal stability. The scales showed theory-consistent relations with external criteria including measures of psychopathy, internalizing/externalizing psychopathology, antisocial behavior, and substance use. Findings demonstrate the viability of measuring triarchic traits in the RFAB sample, extend the known nomological network of these traits into the developmental realm, and provide a foundation for follow-up studies examining the etiology of psychopathic traits and their relations with multimodal measures of cognitive-affective function and proneness to clinical problems.