Moderation effects in personality disorder research.

Abstract

Tests of statistical interactions (or tests of moderation effects) in personality disorder research are a common way for researchers to examine nuanced hypotheses relevant to personality pathology. However, the nature of statistical interactions makes them difficult to reliably detect in many research scenarios. The present study used a flexible, simulation-based approach to estimate statistical power to detect trait-by-trait interactions common to psychopathy research using the Triarchic model of Psychopathy and the Psychopathic Personality Inventory. Our results show that even above-average sample sizes in these literatures (e.g., N = 428) provide inadequate power to reliably detect trait-by-trait interactions, and the sample sizes needed to detect interaction effect sizes in realistic scenarios are extremely large, ranging from 1,300 to 5,200. The implications for trait-by-trait interactions in psychopathy are discussed, as well as how the present findings might generalize to other areas of personality disorder research. We provide recommendations for how to design research studies that can provide informative tests of interactions in personality disorder research, but also highlight that a more realistic option is to abandon the traditional approach when testing for interaction effects and adopt alternative approaches that may be more productive.

Do the Big Five personality traits interact to predict life outcomes? Systematically testing the prevalence, nature, and effect size of trait-by-trait moderation

“…It is also likely that researchers’ verbal theories are consistent with simple additive effects and there is no need to test for an interaction. Vize and colleagues (in press) highlight such a case for trait-by-trait interactions in psychopathy research, noting that if both antagonistic traits and disinhibitory traits relate to antisocial behavior on their own (Vize et al, 2019), then their simultaneous presence will lead to greater antisocial behavior than either trait alone so long as their effects are not completely overlapping (i.e., when the traits are so highly correlated as to be almost isomorphic). That is, individuals who are both antagonistic and disinhibited will be the most antisocial of all, and there is no need to invoke a trait-by-trait interaction to explain the consistently strong relation between psychopathy and antisocial behavior.…”

Positive parenting moderates associations between childhood stress and corticolimbic structure

“…Finally, there may be sex-specific effects for neurobiology related to stress, parenting, and their interaction, as there is at least one report of sex differences related to stress, parenting, and neurobiology ( 17 ). However, three-way interactions require extremely large samples ( N > 1,300) for consistency in findings ( 45 ) and appropriate levels of Type I error ( 46 ).…”

Personality dysfunction linked to future aggression in daily life: Findings from two experience sampling studies.

“…The interaction effects should be interpreted with caution given the limitations of interaction approaches generally (Vize et al, 2023) and specifically in this study due to a smaller sample size and low incidences of aggression behavior. With this context, iMEAN-based AMPD scores consistently weakened the link among aggressive urges and behaviors at the between-person level (six of six interactions significant) and daily (within-person) level (two of six interactions significant).…”