Differences Between ADHD Inattentive and Combined Types on the CPT

Two samples of school-age boys with attention-deficit/hyperactivity disorder (ADHD-Combined and ADHD-Inattentive Types) and a non-ADHD control group were administered an AX version of the continuous performance task (CPT) to examine specific sustained attention deficits. Three levels of time-on-task were included to study performance declines, and 3 interstimulus intervals were included to examine vigilance deficits. As predicted by R. A. Barkley's and H. C. Quay's behavior inhibition deficit models (R. A. Barkley, 1997; H. C. Quay, 1997), the performance of the ADHD-Combined Type (ADHD-C) participants deteriorated more quickly than the other samples. No significant evidence of vigilance deficits among the inattentive (ADHD-IA) sample was found. These findings suggest that distinct criteria for the two ADHD subtypes may be warranted when the CPT is used for diagnostic assessment, and sustained attention-related declines in performance may be typical of the ADHD-C Type only.     

The Effects of Childhood ADHD Symptoms on Early-onset Substance Use: A Swedish Twin Study

Research has documented that children and adolescents with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of substance use problems. Few studies, however, have focused on early-onset substance use. This study therefore investigated how the two symptom dimensions of ADHD (hyperactivity/impulsivity and inattention) are associated with early-onset substance use, the role of persistent ADHD for the association, and to what extent the association is influenced by genetic and environmental factors. Twins (1,480 pairs) in the Swedish Twin Study of Child and Adolescent Development were followed from childhood to adolescence. ADHD symptoms were measured at age 8–9 and age 13–14 via parent-report, whereas substance use was assessed at age 13–14 via self-report. Results revealed that hyperactive/impulsive symptoms predicted early-onset “sometimes” tobacco use (adjusted odds ratios, 1.12, for one symptom count), controlling for inattentive symptoms and conduct problem behaviors. There is no independent effect of inattentive symptoms on early-onset substance use. Children with persistent hyperactivity/impulsivity (defined as scoring above the 75th percentile at both time points) had a pronounced risk of both early-onset tobacco and alcohol use (adjusted odds ratios from 1.86 to 3.35, compared to the reference group). The associations between hyperactivity/impulsivity and early-onset substance use were primarily influenced by genetic factors. Our results indicated that hyperactivity/impulsivity, but not inattention, is an important early predictor for early-onset substance use, and a shared genetic susceptibility is suggested to explain this association.     

Victimization Mediates the Longitudinal Association Between Depressive Symptoms and Violent Behaviors in Adolescence

Despite evidence of a positive link between depressive symptoms and violent behaviors, the pathways underlying this longitudinal association remain unknown. Depressive symptoms might drive and reinforce victimization which in turn could increase risk of individuals becoming violent towards others. Thus, we tested whether victimization mediated the link between depressive symptoms and violent behaviors using a 6-year longitudinal study of a community sample of adolescents. The sample included 682 Dutch adolescents (54% boys) from an ongoing longitudinal study RADAR (Research on Adolescent Development and Relationships). From ages 13 to 18 years, depressive symptoms, victimization experiences, and violent behaviors were annually assessed. We conducted longitudinal mediation analyses to test pathways to violence in adolescents with depressive symptoms. Longitudinal analyses revealed that victimization mediated the association between depressive symptoms and violent behaviors from early to late adolescence. As part of this, we found that adolescents’ depressive symptoms predicted victimization, and this victimization increased risk of subsequent violent behaviors. In conclusion, links between depressive symptoms and violent behaviors are potentially important to understand adolescent development. Decreasing the occurence of victimization is likely to be an important target for the prevention of violent behaviors in adolescents with depressive symptoms.     

Cognitive Moderators of the Longitudinal Association Between Peer Rejection and Adolescent Depressive Symptoms

This longitudinal study examined peer rejection as a predictor of adolescent depressive symptoms during the critical developmental period associated with substantial increases in the prevalence of girls' depression. In a sample of 158 adolescents aged 15-17 years, a peer nomination, sociometric assessment was conducted to examine adolescents' peer status at an initial time point, along with self-report measures of depressive symptoms, depressogenic attributions, and peer importance. Adolescents completed a second measure of depressive symptoms 17 months later. Results were consistent with integrated cognitive vulnerability-stress and cognitive dissonance models, particularly for girls. Specifically, peer rejection was a significant prospective predictor of depressive symptoms when combined with high levels of importance ascribed to peer status and high levels of adolescents' depressogenic attributional styles.     

Emotion Regulation Mediates the Association Between ADHD and Depressive Symptoms in a Community Sample of Youth

The purpose of this study was to examine the longitudinal relationship between attention-deficit/hyperactivity disorder (ADHD) symptoms, emotion regulation (ER) ability, and depressive symptoms within a diverse community sample of 277 youth, ages 9–12 (56 % male). Participants were drawn from a larger study examining adolescent risk behaviors, and completed annual assessments over 3 years. Youth ADHD symptoms were assessed at Time 1 (T1) using the parent-reported Disruptive Behavior Disorders Rating Scale, ER was assessed with the parent-reported Emotion Regulation Checklist at Time 2 (T2), and youth depressive symptoms were assessed using the self-reported Revised Child Anxiety and Depression Scales at Time 3 (T3). Analyses examined T2 ER as a mediator between T1 ADHD symptoms (including the unique contributions of inattentive [IA] versus hyperactive/impulsive [HI] symptoms) and T3 depressive symptoms. Structural equation modeling (SEM) indicated the path model specified provided an excellent fit to the data. Tests of indirect effects suggested that T2 ER appears to be a significant mechanism that underlies the relationship between T1 ADHD and T3 depression, even when accounting for T1 oppositional defiant and depressive symptoms. Furthermore, while both T1 IA and HI symptoms had significant indirect effects on T3 depression through the mechanism T2 ER, HI proved a more robust predictor of T2 ER than IA. Results of this prospective study support cross-sectional findings pointing to ER as a potential mechanism linking ADHD and depressive symptoms in youth. Clinical implications and future directions are discussed.     

The Genetic Association Between ADHD Symptoms and Reading Difficulties: The Role of Inattentiveness and IQ

Previous studies have documented the primarily genetic aetiology for the stronger phenotypic covariance between reading disability and ADHD inattention symptoms, compared to hyperactivity-impulsivity symptoms. In this study, we examined to what extent this covariation could be attributed to “generalist genes” shared with general cognitive ability or to “specialist” genes which may specifically underlie processes linking inattention symptoms and reading difficulties. We used multivariate structural equation modeling on IQ, parent and teacher ADHD ratings and parent ratings on reading difficulties from a general population sample of 1312 twins aged 7.9–10.9 years. The covariance between reading difficulties and ADHD inattention symptoms was largely driven by genetic (45%) and child-specific environment (21%) factors not shared with IQ and hyperactivity-impulsivity; only 11% of the covariance was due to genetic effects common with IQ. Aetiological influences shared among all phenotypes explained 47% of the variance in reading difficulties. The current study, using a general population sample, extends previous findings by showing, first, that the shared genetic variability between reading difficulties and ADHD inattention symptoms is largely independent from genes contributing to general cognitive ability and, second, that child-specific environment factors, independent from IQ, also contribute to the covariation between reading difficulties and inattention symptoms.     

A Twin Study of ADHD Symptoms in Early Adolescence: Hyperactivity-impulsivity and Inattentiveness Show Substantial Genetic Overlap but Also Genetic Specificity

A previous paper in this journal revealed substantial genetic overlap between the ADHD dimensions of hyperactivity-impulsivity and inattentiveness in a sample of 8-year old twins drawn from a UK-representative population sample. Four years later, when the twins were 12 years old, more than 5,500 pairs drawn from the same sample were rated again on the DSM-IV based Revised Conners’ Parent Rating Scale to assess symptoms on both ADHD dimensions. Heritabilities were high (around 70%) for both hyperactivity-impulsivity and inattentiveness and evidence for etiological sex differences was absent. The critical finding was a genetic correlation of 0.55, indicating that hyperactivity-impulsivity and inattentiveness are substantially influenced by the same genes but that the two dimensions also show large and significant unique genetic effects. These results in early adolescence confirm our findings in middle childhood, providing evidence for substantial genetic overlap as well as genetic heterogeneity of the ADHD dimensions. Future genetic studies should investigate the ADHD dimensions separately.     

Relation Between Outcomes on a Continuous Performance Test and ADHD Symptoms Over Time

This study examined the relationship between the developmental trajectories of neuropsychological functioning and ADHD symptomatology in a longitudinal sample of children ages 9 to 14. Participants and measures were derived from the Multimodal Treatment Study for ADHD including 534MTA participants and 254 normal controls. Despite improvement over time, MTA participants continued to receive higher ratings of ADHD symptomatology and exhibit greater difficulties across the majority of neuropsychological outcomes. No relations were found between improvements in neuropsychological functioning and ADHD symptomatology over time. Findings provide support for the persistence of neuropsychological functioning and ADHD symptomatology. Findings did not support the hypothesized relation between improvements in frontally-mediated neuropsychological functioning and ADHD symptomatology possibly due to the brief 1-year lag and limited assessment battery. Findings are discussed in relation to neuropsychological development including recommendations for future research.     

Longitudinal Relations Between Depressive Symptoms and Life Satisfaction Over 15 Years

The longitudinal relationships between depressive symptoms and life satisfaction were examined using the random intercept cross-lagged panel model. This model allows the study of the relationship between the two variables both at the within-person and between-person levels. Data were obtained from the German Ageing Survey (DEAS). Analyses were conducted at lags of 3 (N = 8,492) and 6 years (N = 4,878), with data collected over a period of approximately 15 years. At the within-person level, the bidirectional associations between the two variables were significant in the 3-year lag analysis, whereas in the 6-year lag analysis, only life satisfaction predicted future depressive symptoms. An implication is that dissatisfaction with life may signal the possibility of developing depressive symptoms in the future. Increasing life satisfaction may act as a preventive measure against future depressive symptoms. Depressive symptoms may also be an indicator of future deterioration in subjective well-being.

     

Obsessive Compulsive Symptoms Predict Posttraumatic Growth: A Longitudinal Study

Although posttraumatic growth (PTG) has received growing attention, the relationship between PTG and distress remains unclear. This longitudinal study examines the relationship between posttraumatic obsessive-compulsive (OC) symptoms and PTG. Israeli veterans were followed over 17 years using self-report questionnaires of OC symptoms, posttraumatic stress disorder (PTSD), and PTG. Hierarchical regression analyses demonstrated that OC symptoms predicted PTG, even when initial PTG levels and PTSD symptoms were controlled for in the combatants group. These preliminary findings suggest that OC symptoms may play an important role in facilitating psychological growth. Future research is warranted to explore the mechanisms responsible for this relationship.     

A Twin and Family Study of the Association Between Immune System Dysfunction and Dyslexia Using Blood Serum Immunoassay and Survey Data

We conducted a study of the association between developmental reading disability (DRD) and immune disorders (ID) using both survey and immunoassay data in two separate samples of families. One sample was made up of twins and their parents and was ascertained through a population-based sampling scheme. The other sample was a set of extended pedigrees selected for apparent autosomal dominant transmission of DRD. We failed to find an association between DRD and ID in either sample, regardless of the method used to assess immune system function. Even though our twin sample provided evidence that both DRD and immune conditions were significantly heritable, there was no evidence for a genetic correlation between ID and DRD nor was there any clear indication that a special subgroup of individuals may be comorbid for these conditions because of genetic reasons. How these negative findings can be reconciled with the developmental hypothesis of Geschwind, Behan, Galaburda, and colleagues, and how they may relate to the gene locus influencing DRD that has been recently located in the HLA region of the short arm of chromosome 6 is discussed.     

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

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

     

Interrelations Between Executive Function and Symptoms of Hyperactivity/Impulsivity and Inattention in Preschoolers: A Two Year Longitudinal Study

The present study, including children at risk for developing Attention Deficit Hyperactivity Disorder (ADHD), examined the idea that complex executive functions (EFs) build upon more simple ones. This notion was applied in the study of longitudinal interrelations between core EF components — simple and complex inhibition, selective attention, and working memory (WM) — at age 5 and 6 as well as their predictive relations to ADHD symptoms at age 7. The results showed that simple inhibition and selective attention at age 5 independently predicted complex inhibition and WM at age 6. In addition, EFs primarily predicted symptoms of inattention rather than hyperactivity/impulsivity even at this young age. Finally, age 6 complex inhibition was shown to act as a mediator in the relations between simple inhibition and selective attention at age 5 and symptoms of inattention at age 7. These findings provide novel longitudinal support for the theory that fundamental EF components show a progression with age toward more complex executive control (see Garon et al. Psychological Bulletin 134(1):31–60 2008). Further, complex inhibition, implicating both inhibition and WM, seems to be a particularly strong correlate of ADHD symptoms in young children and should as such be the focus of future studies examining the relation between cognitive function and ADHD symptoms from a developmental perspective.     

Longitudinal Associations Between Perceived Parent-Child Relationship Quality and Depressive Symptoms in Adolescence

This longitudinal study examined bidirectional paths between perceived parent-adolescent relationship quality and depressive symptoms, as well as the moderating role of sex, age, and personality type. 1313 Dutch adolescents (51% girls) from two cohorts (923 12-year olds and 390 16-year olds at Wave 1) reported on their personality, depressive symptoms, and perceived relationship quality to parents in four waves. Consistent with a relationship erosion perspective, depressive symptoms negatively predicted perceived relationship quality with parents. Relationship quality to mothers predicted depressive symptoms for boys and girls, but relationship quality to fathers predicted depressive symptoms only for boys. Personality type only moderated initial associations between relationship quality with mothers and depressive symptoms, which were stronger for Overcontrollers and Undercontrollers than for Resilients. Results thus reveal a pattern of mutual influence between perceived relationship quality and depressive symptoms that is moderated by the interplay among parent and adolescent sex and adolescent personality type.     

A Review of Factors that Promote Resilience in Youth with ADHD and ADHD Symptoms

The vast majority of research on youth with ADHD has focused on risk factors and describing the types of impairment individuals with ADHD experience. However, functional outcomes associated with ADHD are heterogeneous, and although many youth with ADHD experience significant negative outcomes (e.g., school dropout), some are successful in multiple domains of functioning (e.g., pursue and graduate college). There is a growing body of literature supporting the existence of factors that protect youth with ADHD from experiencing negative outcomes, but there is no published synthesis of this literature. Accordingly, the goals of this review are to conceptualize risk–resilience in the context of ADHD using a developmental psychopathology framework and to systematically review and critique evidence for promotive and protective factors in the context of ADHD. The literature search focused specifically on resilience in the context of ADHD symptoms or an ADHD diagnosis and identified 21 studies, including clinic, school, and community samples. Findings of promotive and/or protective factors are summarized across individual, family, and social–community systems. Overall, we know very little of the buffering processes for these youth, given that the study of promotive and protective factors in ADHD is in its infancy. The strongest evidence to date was found for social- and family-level systems. Specifically, multiple longitudinal studies support social acceptance as a protective factor, buffering against negative outcomes such as poor academic performance and comorbid depressive symptoms for youth with ADHD. There was also compelling evidence supporting positive parenting as a promotive factor. In terms of individual-level factors, positive or modest self-perceptions of competence were identified as a promotive factor in multiple studies. Future directions for research that will catalyze the study of resilience with ADHD are provided, and the potential for targeting protective mechanisms with intervention and prevention is discussed.     

Semantic Language as a Mechanism Explaining the Association between ADHD Symptoms and Reading and Mathematics Underachievement

ADHD is associated with academic underachievement, but it remains unclear what mechanism accounts for this association. Semantic language is an underexplored mechanism that provides a developmental explanation for this association. The present study will examine whether semantic language deficits explain the association between ADHD and reading and mathematics underachievement, taking into account alternative explanations for associations, including verbal working memory (WM) impairments, as well as specificity of effects to inattentive and hyperactive-impulsive ADHD symptom domains. Participants in this cross-sectional study were 546 children (54?% male) ages six to twelve (M?=?9.77, SD?=?1.49). ADHD symptoms were measured via maternal and teacher report during structured interviews and on standardized rating forms. Children completed standardized semantic language, verbal WM, and academic testing. Semantic language fully mediated the ADHD-reading achievement association and partially mediated the ADHD-mathematics achievement association. Verbal WM also partially mediated the ADHD-mathematics association but did not mediate the ADHD-reading achievement association. Results generalized across inattentive and hyperactive-impulsive ADHD symptom domains. Semantic language explained the association between ADHD and reading underachievement and partially explained the association between ADHD and mathematics underachievement. Together, language impairment and WM fully explained the association between ADHD and reading underachievement, in line with developmental models suggesting that language and WM conjointly influence the development of attention and subsequent academic achievement. This work has implication for the development of tailored interventions for academic underachievement in children with ADHD.     

Exploring the Relationship Between Autistic-Like Traits and ADHD Behaviors in Early Childhood: Findings from a Community Twin Study of 2-Year-Olds

Behaviors characteristic of autism and ADHD emerge in early childhood, yet research investigating their comorbidity has focused on older children. This study aimed to explore the nature of the relationship between autistic-like traits and ADHD behaviors in a community sample of 2-year-olds. Twins from the Boston University Twin Project (N = 312 pairs) were assessed by their parents on autistic-like traits and ADHD behaviors using the Childhood Behavior Checklist. Phenotypic analyses showed that after controlling for general cognitive ability and socioeconomic status, autistic-like traits (total scale as well as social and nonsocial subscales) correlated positively with ADHD behaviors (r = 0.23–0.26). Structural equation model-fitting analyses revealed that there were modest shared genetic influences between ADHD- and autistic traits (genetic correlation = 0.27) as well as some common environmental influences explaining their covariation. Implications for identifying shared biological pathways underlying autistic-like traits and ADHD behaviors are discussed.     

Disentangling the Associations Between Autistic-Like and Internalizing Traits: A Community Based Twin Study

Internalizing difficulties are prevalent in children with autism spectrum disorders (ASD), yet little is known about the underlying cause of this comorbidity. It is also unclear which types of autistic-like and internalizing difficulties are most strongly associated. The current study investigated the phenotypic and etiological associations between specific autistic-like traits and internalizing traits within a population-based sample. Parent-reported data were analyzed from 7,311 twin pairs at age 7 to 8?years. Structural equation modeling revealed distinguishable patterns of overlap between the three autistic-like traits (social difficulties, communication problems and repetitive/restricted behaviors) and four subtypes of internalizing traits (social anxiety, fears, generalized anxiety, negative affect). Although all phenotypic associations were modest (rph?=?0.00-0.36), autistic-like communication impairments and repetitive/restricted behaviors correlated most strongly with generalized anxiety and negative affect both phenotypically and genetically. Conversely, autistic-like social difficulties showed little overlap with internalizing behaviors. Disentangling these associations and their etiological underpinnings may help contribute to the conceptualization and diagnosis of 'comorbidity' within ASD and internalizing disorders.