Personality Mediation of Genetic Effects on Attention-Deficit/Hyperactivity Disorder

Abstract

Personality traits may be viable candidates for mediators of the relationship between genetic risk and ADHD. Participants were 578 children (331 boys; 320 children with ADHD) between the ages of six and 18. Parents and teachers completed a comprehensive, multistage diagnostic procedure to assess ADHD and comorbid disorders. Mother completed the California Q-Sort to assess child Big Five personality traits. Children provided buccal samples of DNA which were assayed for selected markers on DRD4, DAT1, and ADRA2A. An additive genetic risk composite was associated with ADHD symptoms and maladaptive personality traits; maladaptive personality traits were associated with ADHD symptoms. Low conscientiousness and high neuroticism partially mediated the relationship between genetic risk and ADHD symptoms. Mediation effects for conscientiousness were specific to inattentive symptoms; effects for neuroticism generalized to all disruptive behaviors. High neuroticism and low conscientiousness may be useful as early markers for children at risk for ADHD.

Diversity in Pathways to Common Childhood Disruptive Behavior Disorders

“…Further, past work has indicated that the topics of inter-parental disputes are differentially related to children’s reactions and behaviors, such that conflict regarding the child is linked to greater behavioral dysregulation than are other sources of inter-parental conflict (e.g., financial concerns, Cummings & Davies, 2002). Theoretically, self-blame associated with inter-parental conflict seems to predispose children to adopt a negative interpersonal style that then characterizes their interactions with others and may increase dispositional traits like neuroticism (Martel et al, 2010; Lengua, 2005; Pergamin-Hight, Bakersman-Kranenburg, van IJzendoorn, & Bar-Haim, in press). High neuroticism may, in turn, increase risk for the later development of ODD (Stringaris & Goodman, 2009; Tackett, 2006; Watson et al, 2006), serving as a useful early developmental phenotype of the disorder (Martel, 2009; Sonuga-Barke & Halperin, 2011).…”

“…Recent research and meta-analysis suggests that consistency of parenting may moderate the relationship between DRD4 and ADHD such that homozygosity for the DRD4 promoter 120-bp tandem repeat insertion allele increases vulnerability for ADHD and ODD only in the presence of inconsistent parenting (Nigg, Nikolas, & Burt, 2010; Martel et al, 2010; Sonuga-Barke et al, 2009). Further, child traits like low conscientiousness are influenced by parenting (Lengua, 2005; van den Akker et al, 2010), have been associated with ADHD (Martel & Nigg, 2006; Parker, Majeski, & Collin, 2004), and mediate genetic influences on ADHD (Martel et al, 2010), suggesting that they may be useful developmental phenotypes of the disorder (Sonuga-Barke & Halperin, 2010). Thus, genes influencing dopaminergic neurotransmission may interact with negative environmental socialization influences such as inconsistent parenting that would then lead to decreases in childrens’ conscientiousness which, in turn, leads to the manifestation of ADHD symptomatology.…”

“…Preliminary work utilizing a multiple-level-of-analysis approach has begun to provide some support for these pathway models via evaluation of gene by environment interactions (Martel et al, 2011; Nikolas et al, 2010; Sonuga-Barke et al, 2009) and trait mediation of gene-DBD associations (Martel et al, 2010). Such work suggests that family processes are more or less strongly associated with ADHD symptoms depending on DRD4 genotype (Martel et al, 2011; Sonuga-Barke et al, 2009) and that inter-parental conflict interacts with the serotonin transporter promoter polymorphism (5HTTLPR) to predict ADHD symptoms (Nikolas et al, 2010).…”

“…Such work suggests that family processes are more or less strongly associated with ADHD symptoms depending on DRD4 genotype (Martel et al, 2011; Sonuga-Barke et al, 2009) and that inter-parental conflict interacts with the serotonin transporter promoter polymorphism (5HTTLPR) to predict ADHD symptoms (Nikolas et al, 2010). Further, temperament traits like neuroticism and conscientiousness appear to statistically mediate the associations between genetic risk or susceptibility and ADHD and ODD symptoms (Martel et al, 2010). Thus, these hypothesized multiple-level-of-analysis pathway models have garnered some preliminary support and appear promising with respect to describing childhood ODD and ADHD.…”

“…It was hypothesized that (a) interactions between genetic alleles and parenting and (b) that pathways between etiological environmental and genetic factors and DBD would be mediated by within-child trait mechanisms for both ODD and ADHD, or moderated mediation. Specifically, based on prior work (Martel et al, 2010; Martel et al, 2011; Nikolas et al, 2010; Patterson et al, 1989; Sonuga-Barke et al, 2009), it was predicted that 5HTTLPR genotype would interact with child self-blame for inter-parental conflict to predict ODD symptoms, and that high levels of neuroticism would mediate the effects of this interaction on ODD symptoms. In regard to ADHD, it was predicted that DRD4 promoter polymorphism genotype would interact with inconsistent parenting to predict ADHD symptoms and that low levels of conscientiousness would mediate the effects of this interaction on ADHD symptoms.…”