The cleanest indicators of the genetic rule-breaking and overt aggression factors were, respectively, criteria reflecting truancy and running away and hurting people and initiation of fights. These criteria loaded selectively on 1 genetic common factor or the other, exhibited prominent individual heritabilities (a2 ≥0.35) traceable in large part to their affiliated genetic factor, and had negligible contributions of shared environment (c2 ≤0.03). These findings diverged somewhat from those of Barker et al,28 who reported evidence of a common genetic factor underlying teacher-rated behaviors classified as “aggressive” and “deceptive.” Aside from differences in mode of assessment (ie, teacher ratings vs self-report) and model specification (ie, correlated vs uncorrelated factors), the 2 studies differed in the number and types of behavioral indicators used. In particular, 3 of the 4 DSM-based indicators in the current study that “pulled” most strongly for separate genetic factors (ie, truancy, running away, and hurting people) were not represented in the Barker et al study, which relied on non-DSM indicators.
