Fluid Reasoning Mediates the Association of Birth Weight With ADHD Symptoms in Youth From Multiplex Families With ADHD

Abstract

Objective We tested mediation of birth weight and ADHD symptoms by multiple biologically plausible neurocognitive functions and evaluated familiality of observed indirect effects. Method 647 youth from 284 multiplex families with ADHD completed the Arithmetic, Digit Span, Vocabulary, and Block Design subtests of the Wechsler Intelligence Scale for Children (WISC). Multiple mediation tested WISC subtests as mediators of birth weight and multi-informant ADHD symptoms. Familiality of indirect effects was estimated via moderated mediation comparing conditional indirect effects across siblings concordant and discordant for ADHD. Results Controlling for IQ and demographic factors, Arithmetic uniquely mediated birth weight and ADHD symptoms. Conditional indirect effects through Arithmetic did not differ across ADHD concordant and discordant siblings. Conclusion These cross-sectional findings support previous prospective longitudinal research implicating Arithmetic (i.e., fluid reasoning) as a preliminary causal mediator of birth weight and ADHD symptoms, and suggest that this pathway is independent of genetic influences on ADHD.

Pathways from Birth Weight to ADHD Symptoms through Fluid Reasoning in Youth with or without Intellectual Disability

“…Relatedly, although there was a significant total effect predicting CBCL/TRF Attention Problems (i.e., the association of birth weight with CBCL/TRF Attention Problems unadjusted for Arithmetic), the total effect predicting DISC ADHD symptoms was not significant. A significant total effect is not required for the presence of indirect effects (Loeys, Moerkerke, & Vansteelandt, 2015), and indirect effects in the absence of a total effect were also observed in previous mediational studies of birth weight and ADHD (e.g., Morgan, Lee, et al, 2016; Wiggs et al, 2016). However, the lack of a significant total effect underlying DISC ADHD symptoms, which may be attributable to higher power to detect indirect effects relative to the total effect (Loeys et al, 2015), is contrary to the larger literature on birth weight and ADHD.…”

“…Moreover, the observed indirect effect through Arithmetic replicates evidence from separate case-control and sibling studies of ADHD, including similar effect sizes for the indirect effect; this is especially notable given important differences across all studies. Specifically, two previous studies discovered an indirect pathway from birth weight to dimensional measures of ADHD symptoms through Arithmetic, but in ADHD-oriented samples of youth with cognitive development in the typical range: (1) a case-control ADHD study (youth ages 5–10 at baseline and 7–13 at follow-up) that statistically controlled for co-occurring internalizing and externalizing symptoms (Morgan, Loo et al, 2016), and (2) a study of siblings from a broad age range with high genetic load for ADHD that controlled for youth IQ (Morgan, Lee et al, 2016). Importantly, the present study extended hypotheses to a prospective longitudinal sample of youth with or without ID, suggesting that ADHD symptoms have similar etiologies from birth weight in youth with ID and youth with typical cognitive abilities.…”

“…Notably, this study featured temporally ordered predictors, mediators, and outcomes, which is necessary to infer causal mediation (Kraemer, Stice, Kazdin, Offord, & Kupfer, 2001). Second, in a separate cross-sectional study of 5- to 19-year-old youth from multiplex families with ADHD ( n = 647), WISC Arithmetic, but not Digit Span, Vocabulary, or Block Design, mediated birth weight and multi-informant ADHD symptoms, controlling for IQ ( M = 108.87, SD = 15.65, range = 71–152) and demographic factors (Morgan, Lee, & Loo, 2016). Thus, there is strong evidence for an intermediary role of fluid reasoning in pathways from birth weight to ADHD symptoms, at least among youth with cognitive abilities in the typical range.…”

Fluid Intelligence: Review of Foreign Studies

“…Существуют эмпирические свидетельства о снижении флюидного интеллекта у детей с СДВГ (c синдромом дефицита внимания и гиперактивности) [ На данный момент в научном сообществе рассматривается ресурсная функция флюидного интеллекта, благодаря которой снижается выраженность клинических проявлений многих синдромов, в том числе СДВГ. Так, в крупном исследовании, посвященном связи таких показателей, как вес при рождении и выраженность симптомов СДВГ [56], приняли участие 647 детей из мультиплексных по данному заболеванию семей. Общеизвестно, что низкий вес при рождении может отрицательно сказываться на здоровье ребенка, в частности, представляет собой фактор риска в развитии различных когнитивных нарушений детского возраста, в том числе выявлена положительная связь между весом при рождении и развитием синдрома дефицита внимания [56; 59].…”

COMT and DAT1 polymorphisms moderate the indirect effect of parenting behavior on youth ADHD symptoms through neurocognitive functioning

“…Longitudinal and meta-analytic evidence suggest that separable EF facets including response inhibition and visuospatial working memory reliably predict youth ADHD with medium to large effect sizes (Willcutt, Doyle, Nigg, Faraone, & Pennington, 2005). Although less studied than the traditional EF domains, there is also replicated evidence that fluid reasoning, which may subsume EF, predicts ADHD (Biederman et al, 2009; Doyle, Biederman, Seidman, Reske-Nielsen, & Faraone, 2005; Morgan, Lee, & Loo, 2016; Tamm & Juranek, 2012); this association was also observed within a prospective longitudinal design where assessment of fluid reasoning temporally preceded ADHD symptoms (Morgan, Loo, & Lee, 2016), which is necessary to infer causal mediation (Kraemer, Stice, Kazdin, Offord, & Kupfer, 2001). Response inhibition, visuospatial working memory, and fluid reasoning also share key risk factors with ADHD across genetic and neural measures, underscoring their biological plausibility as mediators.…”