The evidence supporting the presence of individual brain structure correlates of the externalizing spectrum (EXT) is sparse and mixed. To date, large-sample studies of brain-EXT relations have mainly found null to very small effects by focusing exclusively on either EXT-related personality traits (e.g., Hyatt et al., 2022) or EXT-related disorders/symptoms (e.g., Mewton et al., 2022). In this preregistered study using IMAGEN data (