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.     

Predicting ADHD Symptoms in Adolescence from Early Childhood Temperament Traits

Extreme levels of certain temperament traits can be early markers of different developmental pathways of attention-deficit/hyperactivity disorder (ADHD). However, the long-term utility of using these traits as predictors of ADHD is not fully known. This study includes 64 male adolescents (M age = 13.5), who have been followed since birth as part of a longitudinal study. The primary aim was to test effortful control (EC), activity level, and anger, measured in early childhood – both with mother’s reports and laboratory assessments –as predictors of ADHD symptoms in adolescence. Further, we investigated the specificity of this prediction to the different ADHD symptom domains. The results demonstrated that early temperament dimensions of EC and activity level were predictive of ADHD symptoms about 10 years later, when the participants reached adolescence. Moreover, activity level showed specificity only to hyperactivity-impulsivity symptoms whereas EC was a predictor of the two symptom domains. Anger had a predictive correlation with ADHD symptoms; however, it did not have a unique predictive contribution. These results emphasize the relevance of EC and activity level in the developmental course of ADHD. Identification of early risk factors can lead to more efficient design and implementation of intervention programs.     

The Separation of ADHD Inattention and Hyperactivity-Impulsivity Symptoms: Pathways from Genetic Effects to Cognitive Impairments and Symptoms

Both shared and unique genetic risk factors underlie the two symptom domains of attention deficit hyperactivity disorder (ADHD): inattention and hyperactivity-impulsivity. The developmental course and relationship to co-occurring disorders differs across the two symptom domains, highlighting the importance of their partially distinct etiologies. Familial cognitive impairment factors have been identified in ADHD, but whether they show specificity in relation to the two ADHD symptom domains remains poorly understood. We aimed to investigate whether different cognitive impairments are genetically linked to the ADHD symptom domains of inattention versus hyperactivity-impulsivity. We conducted multivariate genetic model fitting analyses on ADHD symptom scores and cognitive data, from go/no-go and fast tasks, collected on a population twin sample of 1,312 children aged 7–10. Reaction time variability (RTV) showed substantial genetic overlap with inattention, as observed in an additive genetic correlation of 0.64, compared to an additive genetic correlation of 0.31 with hyperactivity-impulsivity. Commission errors (CE) showed low additive genetic correlations with both hyperactivity-impulsivity and inattention (genetic correlations of 0.17 and 0.11, respectively). The additive genetic correlation between RTV and CE was also low and non-significant at ?0.10, consistent with the etiological separation between the two indices of cognitive impairments. Overall, two key cognitive impairments phenotypically associated with ADHD symptoms, captured by RTV and CE, showed different genetic relationships to the two ADHD symptom domains. The findings extend a previous model of two familial cognitive impairment factors in combined subtype ADHD by separating pathways underlying inattention and hyperactivity-impulsivity symptoms.     

Diagnosis of ADHD in Adults: What Is the Appropriate DSM-5 Symptom Threshold for Hyperactivity-Impulsivity?

Objective: To empirically identify the appropriate symptom threshold for hyperactivity-impulsivity for diagnosis of ADHD in adults. Method: Participants were 88 adults (M [SD] age = 41.69 [11.78] years, 66% female, 16% minority) meeting formal DSM-IV criteria for ADHD combined or predominantly inattentive subtypes based on a structured diagnostic interview keyed to DSM-IV (Conners' Adult ADHD Diagnostic Interview for DSM-IV [CAADID]). All participants also completed the Conners' Adult ADHD Rating Scale (CAARS), which was normed on the general adult population and includes subscales for DSM-IV inattentive and DSM-IV hyperactive-impulsive symptoms. A T-score threshold of 65 (at least 1.5 SD above population mean) on the CAARS DSM-IV hyperactive-impulsive dimension was used to identify participants with empirically elevated symptom severity. Results: Of 88 participating adults, 48 (55%) had a T-score of at least 65 (1.5 SD) on the CAARS DSM-IV Hyperactive-Impulsive scale. Of these, only 25 (52%) met the DSM-IV cutoff of six hyperactive-impulsive symptoms on the CAADID. Thus, approximately half of those who reported empirically elevated hyperactive-impulsive complaints on the CAARS did not concurrently meet the six-symptom DSM-IV cutoff on the CAADID. An alternative cutoff of four hyperactive-impulsive symptoms on the CAADID captured 39 (81%) cases identified by the CAARS. Conclusion: In adults, mandating at least six hyperactive-impulsive symptoms excludes a significant percentage (almost half) of adults who are at least 1.5 SD above the population mean on a dimensional measure of hyperactivity-impulsivity. These data provide a compelling basis for lowering the symptom threshold of hyperactivity-impulsivity for adults in the DSM-5.     

Psychometric properties of an adult ADHD diagnostic interview

Although research has been conducted to support the psychometric properties of rating scales used to assess ADHD in adults, little work has been published examining semi-structured interviews to assess ADHD in adults. The present study examined the test-retest reliability and concurrent validity of the Conners Adult ADHD Diagnostic Interview for Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) in a sample (N = 30) of patients referred to an outpatient clinic. Kappa statistics for individual symptoms of inattention and hyperactivity-impulsivity were in the fair to good range for current report and retrospective childhood report. Kappa values for overall diagnosis, which included all DSM-IV symptoms, were fair for both current (adult) ADHD diagnosis (kappa = .67) and childhood report (kappa = .69). Concurrent validity was demonstrated for adult hyperactive-impulsive symptoms and child inattentive symptoms. The findings are discussed in the context of overall issues pertaining to adult ADHD assessment.     

The Relation Between Sluggish Cognitive Tempo and DSM-IV ADHD

To test the relation between sluggish cognitive tempo (SCT) and DSM-IV ADHD symptoms, parent and teacher ratings of the 18 DSM-IV ADHD items and five potential SCT items were obtained in a community sample of 8-18 year-old twins that was overselected for ADHD and learning disabilities (n = 296). Confirmatory factor analyses revealed that a three-factor model provided the best fit to the data for both parent and teacher ratings. DSM-IV inattention and hyperactivity-impulsivity symptoms loaded on two factors consistent with the DSM-IV model, and five SCT symptoms loaded primarily on a third factor. The SCT and inattention factors were highly correlated, whereas SCT and hyperactivity-impulsivity were weakly related. Both raters indicated that children meeting symptom criteria for the combined and inattentive subtypes exhibited significantly more SCT symptoms than those meeting symptom criteria for hyperactive-impulsive type and the comparison group without ADHD. Children meeting symptom criteria for the inattentive type exhibited significantly more SCT symptoms than those meeting criteria for the combined type, based on teacher ratings. These results suggest that SCT is an internally consistent construct that is significantly associated with DSM-IV inattention.     

Big five dimensions and ADHD symptoms: links between personality traits and clinical symptoms

Attention-deficit/hyperactivity disorder (ADHD) in adulthood is conceptualized as originating in childhood. Despite considerable theoretical interest, little is known about how ADHD symptoms relate to normal personality traits in adults. In 6 studies, the Big Five personality dimensions were related to ADHD symptoms that adults both recalled from childhood and reported concurrently (total N = 1,620). Substantial effects emerged that were replicated across samples. First, the ADHD symptom cluster of inattention-disorganization was substantially related to low Conscientiousness and, to a lesser extent, Neuroticism. Second, ADHD symptom clusters of hyperactivity-impulsivity and oppositional childhood and adult behaviors were associated with low Agreeableness. Results were replicated with self-reports and observer reports of personality in community and clinical samples. Findings support theoretical connections between personality traits and ADHD symptoms.     

Temperament and common disruptive behavior problems in preschool

The study evaluated trait associations with common Disruptive Behavior Disorders (DBD), Oppositional Defiant Disorder (ODD) and Attention-Deficit/Hyperactivity Disorder (ADHD), during an understudied developmental period: preschool. Participants were 109 children ages 3–6 and their families. DBD symptoms were available via parent and teacher/caregiver report on the Disruptive Behavior Rating Scale. Traits were measured using observational coding paradigms, and parent and examiner report on the Child Behavior Questionnaire and the California Q-Sort. The DBD groups exhibited significantly higher negative affect, higher surgency, and lower effortful control. Negative affect was associated with most DBD symptom domains; surgency and reactive control were associated with hyperactivity-impulsivity; and effortful control was associated with ADHD and inattention. Interactive effects between effortful control and negative affect and curvilinear associations of reactive control with DBD symptoms were evident. Temperament trait associations with DBD during preschool are similar to those seen during middle childhood. Extreme levels of temperament traits are associated with DBD as early as preschool.     

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.     

抑郁遗传效应的发展动态性

抑郁的遗传效应存在发展动态性。一方面,在发展过程中,抑郁的遗传率会发生改变,抑郁的风险基因及其与环境的交互作用模式也存在动态变化。另一方面,遗传因素会影响抑郁的发展变化模式。通过梳理既有相关研究,本文从生理成熟因素、表观遗传和发展级联效应三方面分析抑郁遗传效应发展动态性的原因。未来研究应区分重要发展阶段,增加脑功能、性激素、神经生物蛋白以及表观遗传等指标考察抑郁遗传效应的变化模式及其发生机制。     

Trajectories of Attention Deficit Hyperactivity Disorder and Oppositional Defiant Disorder Symptoms as Precursors of Borderline Personality Disorder Symptoms in Adolescent Girls

Little empirical evidence exists regarding the developmental links between childhood psychopathology and borderline personality disorder (BPD) in adolescence. The current study addresses this gap by examining symptoms of attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) as potential precursors. ADHD and BPD share clinical features of impulsivity, poor self-regulation, and executive dysfunction, while ODD and BPD share features of anger and interpersonal turmoil. The study is based on annual, longitudinal data from the two oldest cohorts in the Pittsburgh Girls Study (N = 1,233). We used piecewise latent growth curve models of ADHD and ODD scores from age 8 to 10 and 10 to 13 years to examine the prospective associations between dual trajectories of ADHD and ODD symptom severity and later BPD symptoms at age 14 in girls. To examine the specificity of these associations, we also included conduct disorder and depression symptom severity at age 14 as additional outcomes. We found that higher levels of ADHD and ODD scores at age 8 uniquely predicted BPD symptoms at age 14. Additionally, the rate of growth in ADHD scores from age 10 to 13 and the rate of growth in ODD scores from 8 to 10 uniquely predicted higher BPD symptoms at age 14. This study adds to the literature on the early development of BPD by providing the first longitudinal study to examine ADHD and ODD symptom trajectories as specific childhood precursors of BPD symptoms in adolescent girls.     

Pathways From Depressive Symptoms to Low Social Status

This research examined two pathways through which depressive symptoms contribute to low social status (i.e., neglect and rejection) within the peer group over time: (a) depressive symptoms promote socially helpless behavior and consequent neglect by peers; and (b) depressive symptoms promote aggressive behavior and consequent rejection by peers. These pathways were investigated in independent samples of youth at two developmental stages: middle childhood (2nd–4th grade) and early adolescence (5th–7th grade). In both Study 1 (M age?=?7.97, SD?=?0.37; 338 girls, 298 boys) and Study 2 (M age?=?11.74, SD?=?0.68; 305 girls, 300 boys), youth and their teachers completed questionnaires at three waves. Multi-group comparison path analyses were conducted to examine sex differences in the models. Consistent with expectations, two pathways emerged through which depressive symptoms undermined subsequent social status. Support was not found for the reverse direction of effect nor for developmental or sex differences in the pathways with one exception: In early adolescence, neglect directly predicted depressive symptoms. These findings suggest specificity but also heterogeneity in the effects of depressive symptoms on social status, and identify behaviors that may be targeted for preventing the persistence of depression and its interpersonal consequences.     

Sex differences in ADHD trajectories across childhood and adolescence

Previous studies have hinted at sex differences in developmental trajectories in ADHD symptoms; however, little is known about the nature or cause of these differences and their implications for clinical practice. We used growth mixture modelling in a community‐ascertained cohort of n = 1,571 participants to study sex differences in ADHD symptom developmental trajectories across the elementary and secondary school years. Participants were measured at ages 7, 8, 9, 10, 11, 12, 13, and 15. We found that females were more likely to show large symptom increases in early adolescence while males were more likely to show elevated symptoms from childhood. For both males and females, early adolescence represented a period of vulnerability characterized by relatively sudden symptom increases. Females affected by hyperactivity/impulsivity may be more likely to be excluded from diagnosis due to current age of onset criteria. More attention should be paid to early adolescence as a period of risk for hyperactivity/impulsivity symptom onset or worsening.     

Bidirectional links and concurrent development of parent-child relationships and boys' offending behavior

This study examined different types of longitudinal associations (i.e., directional links and overlapping developmental changes) between children's delinquency and the quality of parent-child relationships from middle childhood to late adolescence. We used 10-wave interview data of 503 boys, their primary caregivers, and their teachers. Our first aim was to unravel the direction of effects between parent-child relationships and children's offending. Cross-lagged panel models revealed bidirectional links over time between poorer quality parent-child relationships and boys' offending across late childhood (age 7-10), early adolescence (age 10-13) and middle adolescence (age 13-16). Second, we examined the associations between mean changes in delinquency, on the one hand, and mean changes in relationship quality, on the other hand. Although parent-child relationships improved during childhood, their quality decreased in early adolescence and remained stable in middle adolescence. Delinquency increased only in middle adolescence. In five out of six models, the slope factors of relationship quality and offending were strongly correlated, indicating that stronger increases in delinquency were associated with stronger decreases in parent-child relationship quality across childhood, early adolescence, and middle adolescence. The discussion focuses on the theoretical implications of these two types of longitudinal associations.     

A Twin Study of the Relationships among Inattention, Hyperactivity/Impulsivity and Sluggish Cognitive Tempo Problems

We investigated the etiological relationships between the three ADHD dimensions of Inattentive Problems (INP), Hyperactivity-Impulsivity Problems (HIP) and Sluggish Cognitive Tempo (SCT) as measured by the CBCL 6–18 questionnaire. Multivariate models were applied to 398 twin pairs (374 boys and 422 girls) aged 8 to 17 years (M?=?13.06, SD?=?2.59) belonging to the population-based Italian Twin Registry. The INP, HIP and SCT problem scores were moderately-to-substantially (range 0.29–0.47) intercorrelated. The best fitting model showed that these 3 dimensions are correlated both at the genetic (correlations’ range: 0.65–0.83) and the environmental (correlations: 0.29 and 0.44) levels, but they are also distinct. While SCT showed moderate heritability and large non-shared environmental influences, variance for both INP and HIP was substantially explained by genetic influences. We also found evidence of negative sibling interaction for INP, implying that a given behavior in one twin leads to an opposite behavior in the co-twin. Our results support at the etiological level the findings of previous psychometric and longitudinal studies of ADHD, which yielded evidence of the 3 distinct—albeit correlated—problem dimensions of inattentiveness, hyperactivity-impulsivity, and sluggish cognitive tempo.     

Reactive vs. proactive antisocial behavior: differential correlates of child ADHD symptoms?

This study examines the relation between proactive and reactive antisocial behavior with Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms. Caregivers of children aged 8 to 15 (n = 84) being evaluated at a child psychiatry outpatient clinic served as participants. Given the conceptual similarity between reactive antisocial behavior (ASB) and particular ADHD symptoms, we hypothesized that ADHD symptoms would be more closely related to reactive than to proactive ASB. Based on peer deviancy training models of ASB, we also hypothesized that the relation between ADHD symptoms and proactive ASB would increase from middle childhood to adolescence. Both hypotheses were supported. These findings suggest that reactive ASB is relatively specific to ADHD symptoms, and that intervening before early adolescence may be critical to prevent the onset of comorbid proactive ASB.     

Emotional/Behavioral Problems and Functional Impairment in Clinic- and Community-Based Children with Attention-Deficit/Hyperactivity Disorder in Taiwan

Using a sample of 268 patients and 137 community-based children with DSM-IV ADHD, and 268 school controls, aged 6–15, this study aimed to compare the emotional/behavioral problems and functional impairment between clinic- and community-based children with ADHD. Children’s ADHD-related symptoms, a wide range of emotional/behavioral problems, and functional impairments were assessed by the psychiatric interviews and self-, parent- and teacher-reported questionnaires. Both ADHD groups scored higher in parent- and teacher-reported ADHD-related symptoms, wide-ranging emotional/behavioral problems, and impairments in the school, peer, family, and leisure time domains than school controls. However, clinic-based children with ADHD had more physical/developmental problems, more severe functional impairments and teacher-reported hyperactivity/impulsivity symptoms, and higher family burdens than their community counterparts. Our findings suggest that a higher maternal educational level, parent’s perceived child functional impairment, teacher’s perceived impaired peer relationship and hyperactivity-impulsivity, and child physical and developmental problems may be related to the psychiatric referrals of children with ADHD.     

Attention-Deficit/Hyperactivity Disorder,Trait Impulsivity,and Externalizing Behavior in a Longitudinal Sample

Attention-deficit/hyperactivity disorder (ADHD) is highly comorbid with and predictive of externalizing behavior, yet is most often examined categorically, not dimensionally. We tested a recently proposed trait impulsivity model by dimensionally examining measures of childhood inattention and hyperactivity/impulsivity separately as predictors of later externalizing behavior in an all-female longitudinal sample of 228 young women. We also examined influences of parenting and peer relations, given the transactional nature and importance of environmental factors. We analyzed the relative contribution of hyperactive/impulsive (HI) and inattentive (IA) symptoms of girls with and without childhood-diagnosed ADHD (M age?=?9.5; 140 ADHD and 88 Comparison) to the development of externalizing behaviors in adolescence (M age?=?14.2) and early adulthood (M age?=?19.6). Authoritarian parenting was examined as a moderator and adolescent externalizing behavior as a mediator of the relation between childhood HI and later externalizing behavior. Childhood HI symptoms significantly predicted multiple externalizing behaviors in adolescence and early adulthood, after accounting for IA and covariates (ΔR ² ranged from 2.6 to 7.5 %). Mother’s authoritarian parenting moderated this relation. Adolescent externalizing behavior mediated the relation between childhood HI symptoms and early adult externalizing behavior. In no case did childhood IA significantly predict externalizing behavior after accounting for HI symptoms. Findings support a trait impulsivity model, as HI symptoms, but not IA symptoms, significantly predicted later externalizing behavior. Results support the importance of dimensional predictors of developmental trajectories. We discuss implications for assessment, intervention, and future research.     

稳定性与可变性：西方儿童青少年“大五”人格发展研究概述

弄清儿童青少年人格发展特点,可为人格发展与教育工作提供参考。文章梳理了近30年西方儿童青少年“大五”人格发展的研究进展,区分了人格发展的两种主要表现形式,并分别从这两方面总结出儿童青少年“大五”人格结构的稳定性、人格特质平均水平的可变性。最后基于现有研究存在的问题,结合当前时代特点,提出未来研究方向。     

Executive functions and ADHD in adults: evidence for selective effects on ADHD symptom domains

Dual-process models of attention-deficit/hyperactivity disorder (ADHD) suggest that both executive functioning and regulatory functions (e.g., processing speed) are involved and that executive function weaknesses may be associated specifically with symptoms of inattention-disorganization but not hyperactivity-impulsivity. Adults aged 18-37 (105 with ADHD, 90 controls) completed a neuropsychological battery. The ADHD group had weaker performance than did the control group (p<.01) on both executive and speed measures. Symptoms of inattention-disorganization were uniquely related to executive functioning with hyperactivity-impulsivity controlled. Inattention was associated with slower response speed, and hyperactivity-impulsivity with faster output speed. Results were not accounted for by IQ, age, gender, education level, or comorbid disorders. Findings are discussed in terms of developmental and dual-process models of ADHD leading into adulthood.