Genetic and environmental influences on the developmental trajectory of callous‐unemotional traits from childhood to adolescence

Abstract

Background: This study examined the genetic and environmental influences underlying baseline level and developmental course of callous-unemotional (CU) traits across childhood and adolescence. Methods: The data on 8,958 twin pairs (3,108 MZ twin pairs and 5,850 DZ twin pairs) from the Twins Early Development Study were analysed. CU traits were assessed at ages 7, 9, 12 and 16 by mothers and analysed using a biometric latent growth model. Results: Individual differences in the baseline level of CU traits were highly heritable (76.5%), while the heritability of the developmental course of CU traits was moderate (43.6%). The genetic influences on baseline level and developmental course of CU traits were mostly nonoverlapping. Nonshared environment made a modest contribution to the baseline level of CU traits (21.7%). Nonshared environmental influences on the developmental course of CU traits were moderate (43.2%), with nearly half of them being the same as those influencing the baseline level and just over half being specific. Shared environmental effects did not contribute to systematic change across childhood and adolescence but were rather age-specific. Conclusions: Our findings demonstrate that rather than only being conceptualized as factors of stability, genes also play a dynamic role in explaining systematic change in CU traits. Genetic effects for the initial risk and subsequent development of CU traits are not the same. In addition to genetic factors, nonshared environmental influences play an important role in explaining why some children will increase or maintain their CU traits over time, whereas other will desist. New genetic and environmental influences with age suggest that repeated, age-tailored interventions may be required throughout development to make a lasting difference in the presentation of CU traits and associated outcomes.

Role of Callous and Unemotional (CU) Traits on the Development of Youth with Behavioral Disorders: A Systematic Review

“…The 52 studies included in the review identified CU traits in samples of youth with different behavioral (ODD, CD) or neurodevelopmental disorders (ADHD, ASD). Sample sizes differed significantly among studies (N = 23 in the study of Kimonis [ 87 ] to N = 8958 in the study of Takahashi [ 88 ]) depending essentially on the study design. One study examined monozygotic twin families [ 36 ].…”

“…To assess psychopathic tendencies in youth, studies also used the Antisocial Process Screening Device (APSD) [ 89 ], in particular the callous-unemotional subscale, e.g., [ 88 ] and the narcissism and impulsivity subscales, e.g., [ 88 ], the Youth Psychopathic Traits Inventory (YPI; [ 90 ]), or the Childhood Psychopathy Scale (CPS, [ 91 ]). One study also used some items of the Strength and Difficulties Questionnaire (SDQ; Goodman, 1997) to assess CU traits [ 88 ], and another used the Preschool Forms of the Achenbach System of Empirically Based Assessment (ASEBA, [ 92 ]) to assess early CU behaviors. Finally, Crum et al [ 70 ] used the CU subscale of the Nova Scotia Modified IOWA Conners (NSIC; [ 93 ]) as the ICU or the APSD were not published at the time of research [ 70 ].…”

“…This table also highlights the different study designs and key methods and shows that most studies are cross-sectional. Moreover, one-third of all selected studies (19/52) used a longitudinal design with two to six assessment points, ranging from six months to nine years, e.g., [ 4 , 88 ].…”

Commentary: Implications for future research on the genetic and environmental causes of callous–unemotional traits – a commentary on Takahashi et al (2020)

“…The paper by Takahashi, Pingault, and Viding (2020) addresses a critically important topic, uses exemplary methodology, and is written very clearly with a masterful grasp of the subject area. As noted by Takahashi et al, there has been substantial research (including work by these authors using this same large twin data set) documenting the strong genetic influence on both CU traits themselves, as well as on the conduct problems displayed by these children.…”

“…© 2020 Association for Child and Adolescent Mental Health. doi:10.1111/jcpp.13291Commentary onTakahashi et al (2020) …”