To Örebro University

Disruptive behavior disorders (e.g., attention-deficit/hyperactivity disorder [ADHD], oppositional defiant disorder [ODD], conduct disorder [CD]) affect 5–10% of youth and represent the primary reason for youth referrals to clinicians (APA, 2013). DSM-V includes callous-unemotional (CU) traits (specifier ‘with prosocial emotions’) to CD (APA, 2013; Frick et al. 2014). Research suggests an association between CU traits and ADHD symptoms (Graziano et al. 2016; Babinski et al. 2017; Haas et al. 2018). The genetic and environmental overlap between CU traits and ADHD symptoms were examined in a sample of 1189 five year-old children using teacher-ratings, the PrEschool Twin Study in Sweden (PETSS). The correlations between CU traits and hyperactivity/impulsivity, and between CU traits and inattention were rp = 0.53, p\0.05 and 0.44, p\0.05, respectively. For CU traits, genetic factors accounted for 25%, p\0.05 of the variance, the shared environment accounted for 48%, p\0.05, and the non-shared environment for 27%, p\0.05. For hyperactivity/impulsivity, genetic factors accounted for 85%, p\0.05 of the variance and the non-shared environment accounted for 15%, p\0.05. For inattention, genetic factors accounted for 43%, p\0.05 of the variance, the shared envi ronment accounted for 38%, p\0.05, and the non-shared environment for 19%, p\0.05. For CU traits and hyperactivity/impulsivity, rg = 0.58 (0.36, 0.88), rc= 0.84 (0.46, 1.00), re= 0.24 (0.10, 0.37). For CU traits and inattention, rg = 0.33 (0.00, 0.61), rc= 0.63 (0.43, 0.82), re= 0.30 (0.17, 0.43). These findings indicate that CU traits and ADHD symptoms partly share a common genetic and environmental etiology.