Youth Polygenic Scores, Youth ADHD Symptoms, and Parenting Dimensions: An Evocative Gene-Environment Correlation Study

Parenting practices and parental symptoms of attention-deficit/hyperactivity disorder (ADHD) have been linked to severity and course of youth ADHD. However, genetically influenced behaviors related to ADHD in youth may also influence parenting behaviors. Polygenic scores (PGS) have been widely used to quantify genetic vulnerability for ADHD but has rarely been used to examine gene-environment correlation effects. The current study examined the direct effects of youth ADHD PGS and its evocative effects on parenting behaviors via youth ADHD symptoms. 803 youth aged 6-18 years (58.5% male) completed a multistage, multi-informant assessment that included measures of parenting practices and youth and parental ADHD symptoms. A mediation model was used to evaluate direct and evocative effects. Furthermore, we examined if these evocative effects remain after controlling for parental ADHD symptoms. Sensitivity analyses across age, sex, and socioeconomic status (SES) as well as restricting ancestry groups to European only ancestry were also conducted. Results indicated that youth ADHD PGS reliably predicted youth ADHD symptoms across all models (βs ranging from 0.18 to 0.26), including across age, sex, and SES and held even with ancestry restricted to the largest group (northern European). Evocative effects emerged such that higher youth PGS significantly predicted more youth ADHD symptoms, which in turn, significantly predicted lower levels of parental involvement and higher levels of poor supervision/monitoring and inconsistent discipline. These effects remained after controlling for parent ADHD symptoms.

The Oregon ADHD-1000: A new longitudinal data resource enriched for clinical cases and multiple levels of analysis

The fields of developmental psychopathology, developmental neuroscience, and behavioral genetics are increasingly moving toward a data sharing model to improve reproducibility, robustness, and generalizability of findings. This approach is particularly critical for understanding attention-deficit/hyperactivity disorder (ADHD), which has unique public health importance given its early onset, high prevalence, individual variability, and causal association with co-occurring and later developing problems. A further priority concerns multi-disciplinary/multi-method datasets that can span different units of analysis. Here, we describe a public dataset using a case-control design for ADHD that includes: multi-method, multi-measure, multi-informant, multi-trait data, and multi-clinician evaluation and phenotyping. It spans > 12 years of annual follow-up with a lag longitudinal design allowing age-based analyses spanning age 7-19 + years with a full age range from 7 to 21. Measures span genetic and epigenetic (DNA methylation) array data; EEG, functional and structural MRI neuroimaging; and psychophysiological, psychosocial, clinical and functional outcomes data. The resource also benefits from an autism spectrum disorder add-on cohort and a cross sectional case-control ADHD cohort from a different geographical region for replication and generalizability. Datasets allowing for integration from genes to nervous system to behavior represent the "next generation" of researchable cohorts for ADHD and developmental psychopathology.

Latent class analysis to characterize neonatal risk for neurodevelopmental differences

BACKGROUND

Neonatal risk factors, such as preterm birth and low birth weight, have been robustly linked to neurodevelopmental deficits, yet it is still unclear why some infants born preterm and/or low birth weight experience neurodevelopmental difficulties while others do not. The current study investigated this heterogeneity in neurodevelopmental abilities by examining additional neonatal morbidities as risk factors, utilizing latent class analysis to classify neonates into groups based on similar neonatal risk factors, and including neonates from the full spectrum of gestational age.

METHODS

Neonates who received neonatal care at an academic public hospital during an almost 10-year period (n = 19,951) were included in the latent class analysis, and 21 neonatal indicators of health were used. Neonatal class, sex, and the interaction between neonatal class and sex were used to examine differences in neurodevelopment at 18 months of age in a typically developing population.

RESULTS

The best fitting model included five infant classes: healthy, hypoxic, critically ill, minorly ill, and complicated delivery. Scores on the parent-rated neurodevelopmental measure differed by class such that infants in the critically ill, minorly ill, and complicated delivery classes had lower scores. There was no main effect of sex on the neurodevelopmental measure scores, but the interaction between sex and neonatal class was significant for three out of five neurodevelopmental domains.

CONCLUSIONS

The current study extends the understanding of risk factors in neurodevelopment by including several neonatal medical conditions that are often overlooked and by using a person-centered, as opposed to variable-centered, approach. Future work should continue to examine risk factors, such as maternal health during pregnancy and medical interventions for newborns, in relation to neonatal risks and neurodevelopment by using a person-centered approach.

Sluggish Cognitive Tempo as a Transdiagnostic Link Between Adult ADHD and Internalizing Symptoms

Objective

Although absent from traditional diagnostic nosologies, Sluggish Cognitive Tempo (SCT) may have transdiagnostic utility given its robust associations with ADHD and internalizing symptoms as well as with cognitive impairments common to these conditions. Within-person variation in SCT symptoms may also serve to link ADHD, cognitive deficits, and internalizing psychopathology, however, few studies have utilized intensive longitudinal designs to probe within-person variation in SCT and its links to cognitive deficits and psychopathology.

Method

Ecological Momentary Assessment was used to measure between and within-person variance in SCT 4 times per day across 7 days (28 time-points) in 158 college students (approximately 51% with elevated ADHD and/or internalizing symptoms). Participants also completed ratings of current and childhood ADHD symptoms, cognitive function and internalizing psychopathology. Parameters derived from longitudinal multilevel models indexing between and within person variation in SCT were examined as mediators of the associations between (1) ADHD and internalizing symptoms and (2) self-reported cognitive functioning and internalizing symptoms.

Results

Results indicated that between-person differences in SCT, but not within-person variability, linked current and childhood ADHD and internalizing symptoms. Similarly, problems in time-management and organization influenced internalizing psychopathology via between-person differences in SCT.

Conclusion

Results found that SCT may be a transdiagnostic link bridging mental health comorbidities, cognitive dysfunction, and internalizing psychopathology.

A Meta-Analytic Review of Emotion Regulation Focused Psychosocial Interventions for Adolescents

Emotion regulation (ER) is the ability to monitor, evaluate, and modify one's emotional responses to be appropriate for environmental demands. Poor ER has been considered a transdiagnostic risk factor for a range of internalizing and externalizing disorders and overall decreased well-being in adolescents. A range of evidence-based interventions exist which may improve ER. However, much of the intervention research to date does not include a measure of ER to assess change pre and post treatment, with limited information about the efficacy of these interventions in youth across a range of sample types. There is a clear need for a comprehensive review of the literature examining ER-focused interventions in adolescents with a wide range of presenting disorders. A literature search was originally conducted in January 2020 and an updated search was conducted in February 2021 which elicited 1245 articles, of which 605 were duplicates and were removed. Abstracts of the remaining 640 articles were screened with 121 articles being reviewed in full. Of note, 16 additional articles were identified through references and other sources during this process and were also included in the full review. Of the 137 articles reviewed in full, 41 studies were ultimately included in the present review. The present paper provides a descriptive review of intervention approaches and findings from community prevention programs, programs for war-affected youth, programs for clinical populations, and programs for incarcerated and delinquent adolescents. The overall pooled effect was significantly different from zero based on the pre/post effects [Hedge's g = 0.29, 95% CI (0.22, 0.36)] and the intervention/control effects [Hedge's g = 0.19, 95% CI (0.06-0.32)]. Although neither sex nor age significantly accounted for heterogeneity in effect sizes, there were significant findings for population type (clinical vs. community), with community samples having significantly lower effect sizes on average. Impacts of the different ER measures used and significant methodological variability (e.g., use of control groups, length of intervention) across included studies are discussed. Implications and suggestions for future research are reviewed, specifically, that additional understanding of moderators of effects are needed and that measures used to assess change in ER, both dysregulation and adaptive skill use, may need to more directly align with the intervention's focus and the strategies taught as part of the intervention.

Telomere Length and ADHD Symptoms in Young Adults

Objective: Previous research examining telomeres in individuals with neuropsychiatric disorders shows that greater illness, symptoms, or cognitive impairment are linked with shorter telomeres. However, the relationships of telomere length and neuropsychological processes or psychiatric symptoms are not understood in individuals with Attention Deficit/Hyperactivity Disorder (ADHD). Method: 390 young adults with and without ADHD completed a multi-informant diagnostic assessment and neuropsychological testing battery. Participant DNA was isolated from saliva samples, and telomere length was determined using qPCR. Results: Linear regression models demonstrated the only significant association to survive correction for multiple testing was for childhood hyperactivity-impulsivity symptoms and longer telomere length. Conclusion: Contrary to expectations, longer telomere length in young adults was associated only with childhood ADHD symptoms, particularly hyperactivity-impulsivity, in this sample. These findings are an important demonstration that the neuropsychological deficits and symptoms experienced by individuals diagnosed with ADHD during adulthood may not be negatively associated with telomere length.

Multigroup multilevel structure of the child and parent versions of the Positive and Negative Affect Schedule (PANAS) in adolescents with and without ADHD

The Positive and Negative Affect Schedule (PANAS) has been widely used to assess affect expression. Shortened and adolescent versions of the measure have been created, such as the 10-item PANAS for Children (PANAS-C). However, affect expression often involves substantial intraindividual variability, and no research has examined within-person differences using the 10-item PANAS-C. Moreover, intraindividual variability is a key characteristic of attention-deficit hyperactivity disorder (ADHD), and emotion dysregulation is a key feature of ADHD. The present study examined the factor structure of the 10-item PANAS-C in a sample of adolescents (Mage = 13.17 years) with (n = 156) and without (n = 139) ADHD. A 3-factor (Positive Affect, Fear, Distress) within and a 2-factor (Positive Affect, Negative Affect) between model was found to be best fitting using both parent and adolescent reports. The model demonstrated configural invariance for the adolescent report and scalar invariance for the parent report. These results support the multidimensionality of negative affect in youth with ADHD, even when assessed via the short-version PANAS-C. In future work, it will be important to consider the implications of more discrete types of negative affect expression (fear and distress) found across time at the individual level for assessment and intervention practice. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Barkley Deficits in Executive Functioning Scale (BDEFS): Validation in a Large Multisite College Sample

Despite the importance of daily life executive functioning (EF) for college students' success, few measures exist that have been validated in college students specifically. This study examined the factor structure of the Barkley Deficits in Executive Functioning Scale (BDEFS) in college students. Participants were 1,311 students (ages 18-28 years, 65% female) from five universities in the United States. Additionally, the study examined invariance across sex, age, and attention-deficit/hyperactivity disorder symptoms. Exploratory structural equation modeling provided strong support for the BDEFS five-factor structure though some items had high cross-loadings on multiple factors. Findings generally supported invariance across sex and age; however, loadings, thresholds, and factor means differed based on attention-deficit/hyperactivity disorder symptoms. Stronger support for invariance across sex emerged for a reduced item version that eliminated cross-loading items. Overall, findings provide support for the validity and utility of the BDEFS in college students.

A Meta-Analysis of the Association Between Birth Weight and Attention Deficit Hyperactivity Disorder

A large body of work has investigated the association between birth weight and ADHD and has resulted in mixed findings with regard to the direction and magnitude of this association. Despite the vast amount of research on this topic, a comprehensive and systematic quantification of the association between birth weight and ADHD has yet to be undertaken. A meta-analysis of 88 unique studies (N = 4,645,482) was conducted to quantify the overall effect size of birth weight on ADHD symptoms. Several variables were examined as moderators that may contribute to systematic variation in effect sizes. Overall, birth weight was found to have a small, but significant, association with ADHD symptoms such that individuals born at lower birth weights manifested greater symptoms of ADHD (r = -0.15). Sample type, mean birth weight of the sample, geographic region, the informant of ADHD symptoms, ADHD symptom measurement method, and race were all found to contribute significantly to heterogeneity in effect sizes. Notably, several early life risk factors previously found to be associated with both ADHD and birth weight, gestational age and prenatal smoking exposure, were not found to contribute to heterogeneity in effect sizes. The findings of the current analyses align with the growing recognition that early life adversity contributes to neurodevelopmental difficulties, and the findings highlight the importance of a better understanding of the mechanisms underlying the association between early life risk factors and adverse neurodevelopmental sequela, such as that observed in ADHD.

A meta-analytic review of the association between cortisol reactivity in response to a stressor and attention-deficit hyperactivity disorder

A substantial literature suggests that abnormal cortisol reactivity may be a vulnerability for deleterious mental health outcomes, including ADHD. ADHD has been linked with difficulty in emotion regulation and increased risk of experiencing stressors, both of which may be related to psychobiological abnormalities (e.g., abnormal cortisol reactivity). Research has been mixed regarding the association between cortisol reactivity and ADHD. Therefore, the present meta-analytic review (k = 12) sought to quantify this association and review the relevant methodological issues and theoretical implications of this area of research. Overall, no effect was found between cortisol reactivity and ADHD (r = 0), although significant heterogeneity in the analyses suggested that there might be moderators of this association, if one does exist. Results highlight the importance of addressing limitations of the current literature on cortisol reactivity and ADHD and exploring additional indices of emotion regulation that may be associated with ADHD. Implications for future research efforts are discussed.

Sluggish Cognitive Tempo Symptoms Contribute to Heterogeneity in Adult Attention-Deficit Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) persists into adulthood in over 50% of cases, although its associated symptom profiles, comorbid problems, and neuropsychological deficits change substantially across development. Sluggish cognitive tempo (SCT) symptoms may contribute to associations between ADHD and comorbid problems and may partially explain the substantial heterogeneity observed in its correlates. 349 adults aged 18-38 years (M = 23.2, SD = 4.5, 54.7% male, 61.03% with ADHD) completed a multi-informant diagnostic procedure and a comprehensive neuropsychological battery. Adults with ADHD (n = 213) were retained for analyses. Latent class analyses (LCA) revealed three profiles of SCT symptoms among those with ADHD, which we classified as minimal, moderate, or severe SCT. Multiple analysis of covariance (MANCOVA) revealed significant differences among these profiles, which remained when controlling for persistence of ADHD symptoms and sex. In general, adults with ADHD combined with SCT symptoms (moderate and severe) had significantly more symptoms of anxiety, depression, and persistent inattention, and had more severe professional and relational impairment compared to ADHD adults without SCT. Compared to those with moderate or minimal SCT symptoms, the severe SCT group had the most symptoms of depression and internalizing disorders, and the most impairment in the domain of daily responsibility. No significant differences based on externalizing symptoms emerged when controlling for sex and persistence of inattention symptoms, suggesting the moderate and severe SCT groups do not simply reflect more symptoms. Moreover, follow-up mediation analyses revealed that SCT might at least partially explain the heterogeneity in ADHD. Findings have implications for refinement of etiological conceptualization, assessment methods, and intervention strategies.

DRD4 Variants Moderate the Impact of Parental Characteristics on Child Attention-Deficit Hyperactivity Disorder: Exploratory Evidence from a Multiplex Family Design

Parental ADHD symptomatology and related impairments have been robustly associated with youth ADHD across decades of work. Notably, these factors may impede typical development of child self-regulation capabilities through both neurobiological and interpersonal processes. High heritability of estimates for the disorder further suggest that these effects are likely genetically-mediated, at least in part. Variation within the dopamine D4 receptor gene (DRD4) has been shown to moderate parental influences on youth ADHD. Use of a multiplex family design (i.e., samples of families that included multiple affected members) may facilitate identification of additional gene variants of interest and advance understanding of gene-environment interplay in regard to parenting. Thirty multiplex families consisting of 114 individuals (66 youth, 48 parents) completed a multi-stage, multi-informant diagnostic and neurocognitive assessment, measures of parenting, and provided saliva samples for DNA analyses. Sanger sequencing of the DRD4 gene yielded 16 rare variants; a polygenic risk score was computed for both parents and youth. Generalized estimating equations (GEE) examined the predictive effects of parental ADHD symptoms, parental neurocognitive functioning, and poor parenting dimensions on youth ADHD as well as moderation of these effects by parental and youth DRD4 variants. Findings indicated that parental DRD4 variants moderated the impact of parental ADHD and neurocognitive functioning on youth ADHD symptoms. Youth DRD4 variants moderated the impact of parental inconsistent discipline on child ADHD. In all cases, stronger associations were observed for those individuals with more risk variants. These exploratory findings highlight the potential utility of a multiplex family design for examining the interplay between parent and child characteristics in predicting youth outcomes.

A meta-analytic review of the association between pubertal timing and psychopathology in adolescence: Are there sex differences in risk?

Research examining pubertal timing effects on psychopathology has emphasized that a subset of adolescents, particularly females, who experience early pubertal maturation relative to their peers appear to be at increased risk for psychopathology. The aims of the current meta-analysis were (a) to quantify the magnitude of early pubertal timing effects on psychopathology, (b) to examine potential moderators of pubertal timing effects (sex, psychopathology domain, sample composition, measurement method, and mean sample age), and (c) to examine findings in relation to hypotheses in the extant literature explicating differential pubertal timing effects for early versus late youth and males versus females. A systematic literature search was conducted in PubMed and PsycINFO databases and 101 articles met criteria for inclusion. Included studies reported a quantitative association between pubertal timing and higher-order broadband dimensions of psychopathology (i.e., internalizing, externalizing), and/or lower-order subdomains (i.e., distress, fear, antisocial behavior, substance abuse, eating pathology). Using meta-analytic methods, we estimated global effect sizes (Cohen's ds) for the association between pubertal timing and psychopathology. Adolescent sex did not moderate early pubertal timing effects on emotional and behavior problems. However, robust early pubertal timing effects emerged for both males and females across all domains of psychopathology that were small in magnitude (ds∼.20). Measurement method of pubertal timing, but not sample composition or mean sample age, significantly contributed to the heterogeneity of effect sizes across studies. Findings have implications for refinement of theoretical models of pubertal timing effects on psychopathology and highlight the importance of empirical work that can identify pathways which may link offset pubertal timing to psychopathology during adolescence. (PsycINFO Database Record

Pre- and Perinatal Risk for Attention-Deficit Hyperactivity Disorder: Does Neuropsychological Weakness Explain the Link?

Etiological investigations of attention-deficit hyperactivity disorder (ADHD) and disruptive behavior problems support multiple causal pathways, including involvement of pre- and perinatal risk factors. Because these risks occur early in life, well before observable ADHD and externalizing symptoms emerge, the relation between risk and symptoms may be mediated by neurodevelopmental effects that manifest later in neuropsychological functioning. However, potential dissociable effects of pre/perinatal risk elements on ADHD and familial confounds must also be considered to test alternative hypotheses. 498 youth aged 6-17 years (55.0 % male) completed a multi-stage, multi-informant assessment including parent and teacher symptom reports of symptoms and parent ratings of pre/perinatal health risk indicators. Youth completed a neuropsychological testing battery. Multiple mediation models examined direct effects of pre- and perinatal health risk on ADHD and other disruptive behavior disorder symptoms and indirect effects via neuropsychological functioning. Parental ADHD symptoms and externalizing status was covaried to control for potential familial effects. Effects of prenatal substance exposure on inattention were mediated by memory span and temporal processing deficits. Further, effects of perinatal health risk on inattention, hyperactivity-impulsivity, and ODD were mediated by deficits in response variability and temporal processing. Further, maternal health risks during pregnancy appeared to exert direct rather than indirect effects on outcomes. Results suggest that after controlling for familial relatedness of ADHD between parent and child, early developmental health risks may influence ADHD via effects on neuropsychological processes underpinning the disorder.

Sex moderates the impact of birth weight on child externalizing psychopathology

Low birth weight (LBW) has consistently been associated with childhood attention deficit/hyperactivity disorder (ADHD), and a similar association has been found for childhood externalizing disorders, such as oppositional defiant disorder (ODD) and conduct disorder (CD), albeit to a lesser degree. Although the association between LBW and these disorders has been robustly replicated, few studies have adequately controlled for confounding variables, such as parental age at birth and prenatal tobacco use, examined the specificity of the risk of LBW for ADHD symptoms, or investigated potential nonlinear (i.e., quadratic) effects of birth weight (BW). Additionally, the extent to which LBW confers risk for these disorders depending on childhood sex has rarely been examined. The current study examined associations between BW and ADHD, ODD, and CD symptom dimensions as well as the extent to which such associations are moderated by child sex, while also controlling for confounding variables. Significant interactions between sex and BW emerged across all analyses predicting ADHD and externalizing psychopathology, such that associations were stronger in males relative to females. Results remained when controlling for a number of confounds, including parental age, prenatal tobacco use, comorbid psychopathology, as well as other indicators of maternal and child health during the pre- and perinatal period. Both linear and quadratic associations emerged between BW and both hyperactivity and CD symptoms, whereas BW predicted inattention and ODD symptoms in a linear fashion. Future research should continue to investigate the impact of BW on ADHD and externalizing psychopathology, in particular, the biological mechanisms underlying this association. (PsycINFO Database Record

Does Child Temperament Play a Role in the Association Between Parenting Practices and Child Attention Deficit/Hyperactivity Disorder?

Ineffective parenting practices may maintain or exacerbate attention deficit/hyperactivity disorder (ADHD) symptoms and shape subsequent development of disruptive behavior disorders (DBD's) in youth with ADHD. Recent theoretical models have suggested that parenting may exert effects on ADHD via its role in child temperament. The current study aimed to evaluate the indirect effects of parenting dimensions on child ADHD symptoms via child temperament. Youth ages 6-17 years (N = 498; 50.4 % ADHD, 55 % male) completed a multi-stage, multi-informant assessment that included parent, child, and teacher report measures of parenting practices, child temperament, and ADHD symptoms. Statistical models examined the direct and indirect effects of maternal and paternal involvement, poor supervision, and inconsistent discipline on inattention and hyperactivity-impulsivity via child temperament and personality traits. Results indicated differential patterns of effect for negative and positive parenting dimensions. First, inconsistent discipline exerted indirect effects on both ADHD symptom dimensions via child conscientiousness, such that higher levels of inconsistency predicted lower levels of conscientiousness, which in turn, predicted greater ADHD symptomatology. Similarly, poor supervision also exerted indirect effects on inattention via child conscientiousness as well as significant indirect effects on hyperactivity-impulsivity via its impact on both child reactive control and conscientiousness. In contrast, primarily direct effects of positive parenting (i.e., involvement) on ADHD emerged. Secondary checks revealed that similar pathways may also emerge for comorbid disruptive behavior disorders. Current findings extend upon past work by examining how parenting practices influence child ADHD via with-in child mechanisms and provide support for multi-pathway models accounting for heterogeneity in the disorder.

Risky bicycling behavior among youth with and without attention-deficit hyperactivity disorder

BACKGROUND

Injury risk from car-bicycle collisions is particularly high among youth with attention-deficit hyperactivity disorder (ADHD). Here, we capitalized on advances in virtual environment technology to safely and systematically examine road-crossing behavior among child cyclists with and without ADHD.

METHODS

Sixty-three youth (26 with ADHD, 37 non-ADHD controls) ages 10-14 years crossed 12 intersections with continuous cross-traffic while riding a high-fidelity bicycling simulator. Traffic density (i.e., temporal gaps between vehicles) was manipulated to examine the impact of varying traffic density on behavioral indices of road crossing, including gap selection, timing of entry into the roadway, time to spare when exiting the roadway, and close calls with oncoming cars. In addition, parents filled out questionnaires assessing their child's ADHD symptomatology, temperamental characteristics, bicycling experience, and injury history.

RESULTS

ADHD youth largely chose the same size gaps as non-ADHD youth, although ADHD youth were more likely to select smaller gap sizes following exposure to high-density traffic. In addition, youth with ADHD demonstrated poorer movement timing when entering the intersection, resulting in less time to spare when exiting the roadway. Hyperactivity-impulsivity symptoms were specifically associated with selection of smaller gaps, whereas timing deficits were specifically associated with inattention and inhibitory control.

CONCLUSION

Findings highlight two related yet potentially dissociable mechanisms that may influence injury risk among youth with ADHD and provide a foundation for development of injury prevention strategies.

Variation in an Iron Metabolism Gene Moderates the Association Between Blood Lead Levels and Attention-Deficit/Hyperactivity Disorder in Children

Although attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental condition, there is also considerable scientific and public interest in environmental modulators of its etiology. Exposure to neurotoxins is one potential source of perturbation of neural, and hence psychological, development. Exposure to lead in particular has been widely investigated and is correlated with neurodevelopmental outcomes, including ADHD. To investigate whether this effect is likely to be causal, we used a Mendelian randomization design with a functional gene variant. In a case-control study, we examined the association between ADHD symptoms in children and blood lead level as moderated by variants in the hemochromatosis (HFE) gene. The HFE gene regulates iron uptake and secondarily modulates lead metabolism. Statistical moderation was observed: The magnitude of the association of blood lead with symptoms of ADHD was altered by functional HFE genotype, which is consistent with a causal hypothesis.

Does 5HTTLPR Genotype Moderate the Association of Family Environment With Child Attention-Deficit Hyperactivity Disorder Symptomatology?

Problematic family dynamics are common among youth with attention-deficit hyperactivity disorder (ADHD). Multiple mechanisms, including diathesis-stress (vulnerability) and differential susceptibility Gene × Environment interaction effects (G × E), have been proposed to account for this association. G × E effects for ADHD were examined via interactions between a genetic marker hypothesized to influence sensitivity to the environment (the promoter polymorphism of the serotonin transporter gene -5HTTLPR) and family conflict and cohesion in predicting ADHD symptoms. There were 498 youth ages 6-17 years (251 ADHD, 213 non-ADHD) and their parents who completed a multistage, multi-informant assessment (including parent and youth reports on the Family Environment Scale), and saliva sample collection for genotyping. Linear regression analyses examined interactions between 5HTTLPR genotype and the Family Environment Scale scales of conflict and cohesion reported by parent and child. Criteria laid out by Roisman et al. ( 2012 ) were applied to evaluate diathesis stress versus differential susceptibility G × E mechanisms. Results demonstrated interactions between 5HTTLPR genotype and both conflict and cohesion in predicting inattention but not hyperactivity-impulsivity. Both interactions were highly consistent with differential susceptibility models of G × E effects. 5HTTLPR genotype appeared to moderate the relationship between family conflict/cohesion and inattentive symptoms. Interactions highlight the role of 5HTTLPR genotype as a potential marker of environmental sensitivity and provide support for differential susceptibility models of G × E effects for ADHD.

Parental involvement moderates etiological influences on attention deficit hyperactivity disorder behaviors in child twins

Although few would now contest the presence of Gene × Environment (G × E) effects in the development of child psychopathology, it remains unclear how these effects manifest themselves. Alternative G × E models have been proposed (i.e., diathesis-stress, differential susceptibility, bioecological), each of which has notably different implications for etiology. Child twin studies present a powerful tool for discriminating between these models. The current study examined whether and how parental involvement moderated etiological influences on attention deficit hyperactivity disorder (ADHD) within 500 twin pairs aged 6-11 years. Results indicated moderation of genetic and nonshared environmental contributions to ADHD by parental involvement, and moreover, suggested both differential susceptibility and bioecological models of G × E. Results highlight the utility of child twin samples in testing different manifestations of G × E effects.

Executive function assessment and adult attention-deficit/hyperactivity disorder: tasks versus ratings on the Barkley deficits in executive functioning scale

Adults with attention-deficit/hyperactivity disorder (ADHD) exhibit variable impairments on executive function (EF) tasks. Due to this variability, ratings of EF (rather than tasks) have been proposed as an alternative method that better captures symptom severity and impairment among adults with ADHD. However, few studies have jointly examined performance across multiple neuropsychological domains and EF ratings as predictors of severity and impairment among adults with ADHD. Adults (N = 273) ages 18-38 years (M = 22.6 years, 55.3% male, 62.2% with ADHD) completed a comprehensive diagnostic and neurocognitive assessment, which included self and informant ratings of ADHD symptom severity and EF and tasks of arousal/activation, response inhibition, set shifting, interference control, and working memory. Hierarchical linear regression models indicated that tasks of arousal/activation and response inhibition uniquely predicted ADHD symptom dimensions and related impairments. Over and above EF task performance, EF ratings of time management significantly predicted increased inattention (β = .209, p < .001, ΔR² = 3.9%), whereas ratings of restraint predicted increased hyperactivity/impulsivity (β = .259, p < .001, ΔR² = 6.4%). Furthermore, EF ratings of time management, restraint, and emotion regulation incrementally accounted for variance in relationship, professional, and daily living impairments over and above EF task performance (ΔR² range = 1.7-7.7%). Results may help refine neurobiological theories and assessment of adult ADHD.

Neuropsychological performance and attention-deficit hyperactivity disorder subtypes and symptom dimensions

OBJECTIVE

Characterization of clinical heterogeneity in attention-deficit hyperactivity disorder (ADHD) remains controversial. Neuropsychological and cognitive studies provide one type of validation data, but too often have considered only a narrow range of functional domains.

METHOD

The current study examined ADHD subtype and presentation differences across a broad range of neurocognitive domains in a large clinically characterized, community-recruited sample of 498 youth (213 control, 107 ADHD-primarily inattentive [ADHD-PI], 137 ADHD-combined [ADHD-C]), ages 6-17 years. Domains assessed included inhibition, working memory, arousal, processing speed, response variability, and temporal information processing.

RESULTS

Youth with ADHD-C performed worse than youth with ADHD-PI in all domains, consistent with a severity model. Performance among a subgroup with a "restrictive inattentive" presentation indicated potential deficits in processing speed relative to other ADHD-PI youth, but no other effects. When all measures were included in the same model, cognitive control (executive functions, working memory, and memory span), arousal, and response variability each provided uniquely incremental statistical prediction of specific symptom dimensions and of subtype/presentation, but temporal information processing and processing speed did not.

CONCLUSION

Results suggest the potential to consolidate multiple neurocognitive theories of ADHD, and that such consolidation will apply across putative clinical subtypes or presentations.

Genetic and environmental influences on ADHD symptom dimensions of inattention and hyperactivity: a meta-analysis

Behavioral genetic investigations have consistently demonstrated large genetic influences for the core symptom dimensions of attention-deficit/hyperactivity disorder (ADHD), namely inattention (INATT) and hyperactivity (HYP). Yet little is known regarding potential similarities and differences in the type of genetic influence (i.e., additive vs. nonadditive) on INATT and HYP. As these symptom dimensions form the basis of the current Diagnostic and Statistical Manual of Mental Disorders subtype classification system, evidence of differential genetic influences would have important implications for research investigating causal mechanisms for ADHD. The current meta-analysis aimed to investigate the nature of etiological influences for INATT and HYP by comparing the type and magnitude of genetic and environmental influences each. A comprehensive literature search yielded 79 twin and adoption studies of INATT and/or HYP. Of these, 13 samples of INATT and 9 samples of HYP were retained for analysis. Results indicated that both dimensions were highly heritable (genetic factors accounted for 71% and 73% of the variance in INATT and HYP, respectively). However, the 2 dimensions were distinct as to the type of genetic influence. Dominant genetic effects were significantly larger for INATT than for HYP, whereas additive genetic effects were larger for HYP than for INATT. Estimates of unique environmental effects were small to moderate and shared environmental effects were negligible for both symptom dimensions. The pattern of results generally persisted across several moderating factors, including gender, age, informant, and measurement method. These findings highlight the need for future studies to disambiguate INATT and HYP when investigating the causal mechanisms, and particularly genetic influences, behind ADHD.