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.     

The Association Between Sluggish Cognitive Tempo and Academic Functioning in Youth with Attention-Deficit/Hyperactivity Disorder (ADHD)

The purpose of the study was to evaluate the relation between Sluggish Cognitive Tempo (SCT) and academic functioning in a sample of 52 adolescents (40 males, 12 females) with Attention-Deficit/Hyperactivity Disorder (ADHD; M _age?=?13.75). This study builds on prior work by utilizing an empirically-based and psychometrically validated measure of SCT, collecting ratings of SCT from both parents and teachers, and examining associations with multiple domains of academic functioning from both the parent and teacher perspective as well as grade point average (GPA). Both SCT and DSM-IV symptoms of inattention were significantly correlated with domains of academic functioning. Multiple regression analyses demonstrated that the parent-rated SCT Slow subscale predicted overall academic functioning, organizational skills impairment, and homework problems above and beyond ADHD symptoms and child and demographic characteristics known to be associated with academics, including intelligence, academic achievement, and family income. The teacher-rated SCT Low Initiation/Persistence subscale also predicted homework problems and was the only SCT variable to predict school grades above and beyond ADHD symptoms and relevant covariates. Both the SCT Slow and Low Initiation/Persistence subscales include items related to youth seeming apathetic, unmotivated, and lacking initiative, behaviors that are strongly related to ADHD symptoms of inattention but not currently captured by the DSM-IV. Implications of these findings towards supporting the external validity of the SCT construct are discussed along with potential implications for intervention.     

DSM-IV-Defined Inattention and Sluggish Cognitive Tempo: Independent and Interactive Relations to Neuropsychological Factors and Comorbidity

The aim of the present study was to investigate the independent relations of DSM-IV-defined inattention and behaviors characteristic of sluggish cognitive tempo (SCT) to neuropsychological factors and problem behaviors often comorbid with attention deficit/hyperactivity disorder (ADHD). By controlling for symptoms of DSM-IV-defined inattention, unique relations to SCT could be ascertained. Additionally, interactive relations of DSM-IV-defined inattention and SCT were of interest. A community-based sample of school children (N = 209; the higher end of the ADHD-symptom range was oversampled) completed neuropsychological tasks designed to measure executive function (EF), sustained attention, and state regulation. Behavioral symptoms were measured using parental and teacher ratings of the DSM-IV criteria for ADHD and Oppositional Defiant Disorder (ODD). The results showed that these two domains of inattention, DSM-IV-defined inattention and SCT, have neuropsychological processes and comorbid behavioral problems in common. However, when controlling for the overlap, DSM-IV-defined inattention was uniquely related to EF and state regulation, while SCT was uniquely related to sustained attention. In addition, the results showed an interactive relation of DSM-IV-defined inattention and SCT to ODD. Findings from the present study support the notion that DSM-IV-defined inattention constitutes a somewhat heterogeneous condition. Such results can further our theoretical understanding of the neuropsychological impairments and comorbid behavioral problems associated with ADHD symptoms.     

Do Parent and Teacher Report of ADHD Symptoms in Children Differ by SES and Racial Status?

Parent and teacher reports of symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in children often differ from each other. These informant report differences may occur in systematic ways that vary by child socioeconomic status (SES) and race, but little is known about how SES and race together relate to parent and teacher report of ADHD symptoms in school-aged children. We examined the relationship between child SES, child race and parent and teacher reports of ADHD symptoms in two samples of school-aged Caucasian and African American children being evaluated for ADHD (N = 1056; N = 317). Multivariate regression was used to predict parent and teacher reports of ADHD symptoms from child SES, race, age, gender and interaction terms. The Wald test of parameter constraints was used to test the contrast between the predictors of interest and parent and teacher report of symptoms. In the second sample, we also examined observer report measures of ADHD symptoms during one-to-one testing and in the classroom. In both samples, lower SES was associated with higher levels of inattention symptoms, as reported by teachers, but not by parents. Lower SES was also associated with higher levels of hyperactivity/impulsivity symptoms, as reported by both teachers and parents. African American race was associated with higher levels of inattention and hyperactivity/impulsivity symptoms reported by teachers than reported by parents. Observer report measures showed a different pattern of associations with SES and race. Investigating how children’s SES and race influence cross-informant agreement on ratings of children’s behavior might lead to the development of better assessment practices and more accurate diagnoses for diverse child populations.     

Validity of the Sluggish Cognitive Tempo, Inattention, and Hyperactivity Symptom Dimensions: Neuropsychological and Psychosocial Correlates

This study examined the latent structure and validity of inattention, hyperactivity-impulsivity, and sluggish cognitive tempo (SCT) symptomatology. We evaluated mother and teacher ratings of ADHD and SCT symptoms in 140 Puerto Rican children (55.7% males), ages 6 to 11?years, via factor and regression analyses. A three-factor model (inattention, hyperactivity-impulsivity, and SCT) provided the best fit for both sets of ratings. Inattention was the strongest correlate of lower scores on neuropsychological, achievement, and psychosocial measures. Externalizing problems were most strongly associated with hyperactivity-impulsivity, and internalizing problems were most strongly associated with parent-rated SCT and teacher-rated Inattention. SCT was not associated with executive function but was negatively associated with math. Inattention accounted for a disproportionate amount of ADHD-related impairment, which may explain the restricted discriminant validity of DSM-IV types. The distinct factors of hyperactivity-impulsivity and SCT had unique associations with impairing comorbidities and are roughly equivalent in predicting external correlates of ADHD-related impairment.     

The Internal and External Validity of Sluggish Cognitive Tempo and its Relation with DSM–IV ADHD

Studies of subtypes of DSM-IV attention-deficit/hyperactivity disorder (ADHD) have provided inconsistent support for the discriminant validity of the combined type (ADHD-C) and predominantly inattentive type (ADHD-I). A large sample of children and adolescents with ADHD (N?=?410) and a comparison group without ADHD (N?=?311) were used to test the internal and external validity of sluggish cognitive tempo (SCT), a dimension characterized by low energy and sleepy and sluggish behavior. SCT scores were then incorporated in analyses of ADHD subtypes to test whether the discriminant validity of ADHD-C and ADHD-I could be improved by including SCT symptoms as part of the criteria for ADHD-I. Factor analyses of parent and teacher ratings indicated that six SCT items loaded on a factor separate from symptoms of ADHD and other psychopathology, providing important support for the internal validity of SCT. The external validity of SCT was supported by significant associations between SCT and measures of functional impairment and neuropsychological functioning when symptoms of ADHD and other psychopathology were controlled. However, contrary to initial predictions, high levels of SCT did not identify a subgroup of ADHD-I that was clearly distinct from ADHD-C. Instead, the current results suggest that DSM-IV inattention and SCT are separate but correlated symptom dimensions that are each independently associated with important aspects of functional impairment and neuropsychological functioning.     

Association of Positive and Negative Parenting Behavior with Childhood ADHD: Interactions with Offspring Monoamine Oxidase A (MAO-A) Genotype

Relatively little is known about the potential interplay between genetic and environmental influences on attention-deficit/hyperactivity disorder (ADHD), including gene-environment interaction (G×E). There is evidence that parenting behavior interacts with offspring genotype in the development of externalizing problems, but studies have largely focused on explicit maltreatment rather than differentiated measures of parenting behavior, including positive and negative parenting. We tested the interactive effects of the 30-base pair variable number tandem repeat (VNTR) polymorphism of the monoamine oxidase A gene (MAO-A) with positive and negative parenting behavior on parent- and teacher ratings of inattention and hyperactivity symptoms among 150 6–9 year-old boys with and without ADHD. Negative parenting predicted parent and teacher ratings of inattention symptoms, but only among boys with high-activity MAO-A genotype. MAO-A genotype did not moderate the association of positive parenting and parent- and teacher ratings of ADHD. We discuss the potential role of interactive exchanges between parenting behavior and child genotype in the development and persistence of ADHD and related behavior problems.     

Are sluggish cognitive tempo symptoms associated with executive functioning in preschoolers?

The aim of this study is to investigate whether sluggish cognitive tempo (SCT) symptoms are associated with neurocognitive task performance and ratings of real-world executive functioning (EF) in preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD). The associations between parent- and teacher-rated SCT symptoms and neuropsychological task performance and ratings of EF in 61 4-year-old preschool children (51 boys, 10 girls) with self-regulation difficulties were examined, with regression analyses controlling for the effects of ADHD inattention symptoms. In the study sample, higher teacher-rated SCT symptoms are significantly associated with poorer performance on tasks of visual-perceptual abilities, auditory and visual attention, sustained and selective attention, inhibitory control, pre-numerical/numerical concepts, and slower processing speed, but SCT symptoms are not significantly associated with working memory, attention shifting or cognitive flexibility when controlling for ADHD inattention. Higher parent-rated SCT symptoms are significantly associated with visual-perceptual abilities. ADHD inattention symptoms are more strongly associated than SCT with daily life EF ratings; neither parent- nor teacher-rated SCT symptoms are significantly associated with daily life ratings of inhibition, working memory, or planning/organization after controlling for ADHD inattention. This study suggests that SCT symptoms contribute to EF deficits at least on neurocognitive tasks assessing visual-perceptual/spatial abilities, attention to detail and processing speed, as observed in this sample of young children at risk for ADHD, and may be an important intervention target.     

Reliable Ratings or Reading Tea Leaves: Can Parent,Teacher, and Clinician Behavioral Ratings of Preschoolers Predict ADHD at Age Six?

To assess the relative ability of parent, teacher, and clinician behavioral ratings of preschoolers to predict ADHD severity and diagnosis at 6 years of age. Hyperactive/inattentive preschoolers [N?=?104, 75 % boys, Mean (SD) age?=?4.37 (0.47) years] were followed over 2 years (mean?=?26.44 months, SD?=?5.66). At baseline (BL), parents and teachers completed the ADHD-RS-IV and clinicians completed the Behavioral Rating Inventory for Children following a psychological testing session. At age 6, [Mean (SD) age?=?6.62 (0.35) years], parents were interviewed with the K-SADS-PL; teachers completed the ADHD-RS-IV; and laboratory measures of hyperactivity, impulsivity, and inattention were obtained from children. Hierarchical logistic and linear regression analyses examined which combination of BL ratings best predicted 6-year-old ADHD diagnosis and severity, respectively. At age 6, 56 (53.8 %) children met DSM-IV criteria for a diagnosis of ADHD. BL ratings from parent/teacher/clinician, parent/teacher and parent/clinician combinations significantly predicted children who had an ADHD diagnosis at age 6. Parent and clinician, but not teacher, behavior ratings were significant independent predictors of ADHD diagnosis and severity at 6-years-old. However, only clinician reports of preschoolers’ behaviors predicted laboratory measures of over-activity and inattention at follow-up. Cross-situationality is important for a diagnosis of ADHD during the preschool years. Among parents, teachers and clinicians, positive endorsements from all three informants, parent/teacher or parent/clinician appear to have prognostic value. Clinicians’ ratings of preschoolers’ inattention, impulsivity and hyperactivity are valid sources of information for predicting ADHD diagnosis and severity over time.     

Evidence for a General ADHD Factor from a Longitudinal General School Population Study

Recent factor analytic studies in Attention-Deficit/Hyperactivity Disorder (ADHD) have shown that hierarchical models provide a better fit of ADHD symptoms than correlated models. A hierarchical model includes a general ADHD factor and specific factors for inattention, and hyperactivity/impulsivity. The aim of this 12-month longitudinal study was to test the generalizability of the hierarchical models of ADHD within an elementary school population of 6–9 year old children (250 boys, 260 girls). Examination of differences as a function of informant (parent vs. teacher ratings), sex, and time was conducted. Six potential factor structures for the 18 items of the SWAN (Strengths and Weaknesses of ADHD-symptoms and Normal-behavior) scale were tested using confirmatory and exploratory factor analyses. Hierarchical models with a general ADHD factor and two or three specific factors best accounted for parent and teacher reports of symptoms for both boys and girls and at two time points separated by a 12-month interval. Findings indicate that the 18 SWAN items measure a common latent trait as well as orthogonal factors or dimensions of inattention and hyperactivity/impulsivity.     

Attention-Deficit/Hyperactivity Disorder Symptoms in Mothers and Fathers: Family Level Interactions in Relation to Parenting

Previous studies linking parent ADHD symptoms to parenting have typically focused on each parent individually. To provide a broader understanding of family context, in this study, levels of inattention and hyperactivity-impulsivity in mothers and fathers were examined, both individually and in combination, in relation to negative parenting and child-rearing disagreements. Two-parent families of 5 to 13 year old boys (126 with ADHD and 53 typically developing) participated. Parents reported their own ADHD symptoms and their perceptions of child-rearing disagreements. Parenting was measured using self-, partner-, and child-reports as well as observations. Controlling for child ADHD symptoms, inattention symptoms in fathers predicted parenting difficulties. For mothers, inattention symptoms were linked to parenting problems only when fathers also had high levels of inattention. In contrast, parenting was most problematic for both mothers and fathers in families in which fathers had higher and mothers had lower levels hyperactivity-impulsivity symptoms. These results remained essentially unchanged when child externalizing behavior and mother depression and hostility were controlled, but father depression reduced the significance of some interactions. The results highlight the importance of the match between father and mother levels of symptoms, and point to differential relations of parenting to inattention and hyperactivity-impulsivity symptoms in parents.     

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.     

Agreement Between Parent and Teacher Ratings of Disruptive Behavior Disorders in Children with Clinically Diagnosed ADHD

This study investigated the agreement between parent and teacher ratings of DSM-IV symptoms of Attention Deficit Hyperactivity Disorder (ADHD) and related disorders: Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD). A sample of 55 children in the age range of 6–12 years with clinically diagnosed ADHD participated in the study. Parents and teachers were asked to complete the Disruptive Behavior Disorder Rating Scale (DBDRS; W. E., Pelham, E. M., Gnagy, K. E., Greenslade, & R. Milich, 1992). No association was found between parent and teacher ratings of inattention and hyperactivity/impulsivity. However, moderate to high levels of agreement were obtained for ratings of symptoms that characterized ODD and CD. The observed low levels of agreement between parent and teacher ratings of ADHD symptoms may be attributed to different perceptions of the problem behavior by parents and teachers, medication effects, or the situation specificity of children's behavior. It is recommended that the diagnostic criterion of symptom pervasiveness for the diagnosis of ADHD be operationalized more clearly.     

Distinguishing sluggish cognitive tempo from attention-deficit/hyperactivity disorder in adults

Researchers who study subtypes of attention-deficit/hyperactivity disorder (ADHD) in children have identified a subset having a sluggish cognitive tempo (SCT) typified by symptoms of daydreaming, mental confusion, sluggish-lethargic behavior, and hypoactivity, among others who differ in many respects from ADHD. No studies have examined the nature and correlates of SCT in adults. This study sought to do so using a general population sample in which those having high levels of SCT symptoms were identified (≥95th percentile) and compared to adults having high levels of ADHD symptoms and adults having both SCT and ADHD symptoms. From a representative sample of 1,249 U.S. adults 18-96 years four groups were created: (a) high levels of SCT but not ADHD (N = 33), (b) high levels of ADHD but not SCT (N = 46), (c) high levels of both SCT and ADHD (N = 39), and (d) the remaining adults as a control group (N = 1,131). As in children, SCT formed a distinct dimension from ADHD symptoms that was unrelated to age, sex, or ethnicity. Adults in both ADHD groups were younger than those with SCT only or control adults. The SCT-only group had less education than the control group, whereas both SCT groups earned less annual income than the control or ADHD-only group. More individuals in the combined group were out of work on disability. In their EF, both SCT groups reported greater difficulties with self-organization and problem solving than controls or the ADHD-only group. Otherwise, the SCT + ADHD group reported significantly greater problems with all other domains of EF than the other groups. But both the SCT-only and ADHD-only groups had significantly more EF difficulties than controls though not differing from each other. A similar pattern was evident on most ratings of psychosocial impairment, except in work and education where SCT was more impairing than ADHD alone and in driving where ADHD was more impairing. SCT contributed unique variance to EF deficits and psychosocial impairment apart from ADHD inattention and hyperactive-impulsive symptoms. Results further suggested that a symptom threshold of 5 or more out of 9 along with a requirement of impairment would result in 5.1% of the population as having SCT. It is concluded that SCT may be a separate disorder from ADHD yet with comorbidity occurring in approximately half of all cases of each. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Social and Academic Impairment in Youth with ADHD, Predominately Inattentive Type and Sluggish Cognitive Tempo

Sluggish cognitive tempo (SCT) was originally identified as a construct that characterized the inattention problems of some children with attention deficit disorder (ADD). Research has indicated that using SCT symptoms to identify a subset of youth with attention-deficit/hyperactivity disorder, predominately inattentive type (ADHD-IT) may elucidate distinct patterns of impairment and thereby improve the external validity of ADHD subtypes. The objective of the current study was to investigate whether youth with clinically-assessed ADHD-IT and high levels of SCT exhibit unique social and academic impairments. In a clinic-referred sample of youth (N?=?209; 23 % female) aged 6 to 17 years, participants who met criteria for three different groups were identified: ADHD, Combined Type (ADHD-CT; n?=?80), ADHD-IT with low SCT symptoms (n?=?74), and ADHD-IT with high SCT symptoms (n?=?55). These groups were compared on indicators of social and academic functioning while considering the effects of co-occurring internalizing and disruptive behavior disorders. Youth with ADHD-IT high in SCT exhibited uniquely elevated withdrawal, as well as low leadership and low peer-directed relational and overt aggression, which were not accounted for by co-occurring disorders. This high-SCT group was also the only group to have more homework problems than the ADHD-CT group, but only when other disruptive behavior disorders were absent. The distinctiveness of the high-SCT group, which was primarily evident in social as opposed to academic functioning, provides partial support for the external validity and clinical utility of SCT.     

Sluggish Cognitive Tempo in Abnormal Child Psychology: An Historical Overview and Introduction to the Special Section

There has recently been a resurgence of interest in Sluggish Cognitive Tempo (SCT) as an important construct in the field of abnormal child psychology. Characterized by drowsiness, daydreaming, lethargy, mental confusion, and slowed thinking/behavior, SCT has primarily been studied as a feature of Attention-Deficit/Hyperactivity Disorder (ADHD), and namely the predominately inattentive subtype/presentation. Although SCT is strongly associated with ADHD inattention, research increasingly supports the possibility that SCT is distinct from ADHD or perhaps a different mental health condition altogether, with unique relations to child and adolescent psychosocial adjustment. This introductory article to the Special Section on SCT provides an historical overview of the SCT construct and briefly describes the contributions of the eight empirical papers included in the Special Section. Given the emerging importance of SCT for abnormal psychology and clinical science, there is a clear need for additional studies that examine (1) the measurement, structure, and multidimensional nature of SCT, (2) SCT as statistically distinct from not only ADHD-inattention but also other psychopathologies (particularly depression and anxiety), (3) genetic and environmental contributions to the development of SCT symptoms, and (4) functional impairments associated with SCT. This Special Section brings together papers to advance the current knowledge related to these issues as well as to spur research in this exciting and expanding area of abnormal psychology.     

Familial Aggregation of ADHD Characteristics

Patterns of familial aggregation of ADHD symptoms in parents of ADHD and non-ADHD children were examined. Within the ADHD sample, symptom aggregation was examined as a function of biological relationship, parent and child gender, and children's comorbid diagnoses. Participants consisted of parents of 579 children with ADHD, Combined Type participating in the multimodal treatment study of children with ADHD and parents of 288 normal control participants. Adult symptoms of ADHD were measured by both self-report and report of a significant other. Results indicated that the parents of children with ADHD had higher ratings of inattention/cognitive problems, hyperactivity/restlessness, impulsivity/emotional lability, and lower self-concept than parents of children without ADHD on both self-report and other-report ratings. Within the ADHD sample of children, other-report ratings of inattention/cognitive problems and impulsivity/emotional lability were higher for biological parents compared to nonbiological parents whereas self-ratings were not related to biological status. These findings support previous research documenting familial aggregation of ADHD and appear to strengthen the hypothesis that there is a genetic contribution to ADHD.     

The Unity and Diversity of Inattention and Hyperactivity/Impulsivity in ADHD: Evidence for a General Factor with Separable Dimensions

To examine the unity and diversity of inattention and hyperactivity/impulsivity symptom domains of Attention-Deficit/Hyperactivity Disorder (ADHD) in a clinical sample of adolescents with ADHD. Parents and adolescents were administered a semi-structured diagnostic interview, the Schedule for Affective Disorders and Schizophrenia for School-Age Children — Present and Lifetime Version (K-SADS-PL), to assess adolescent ADHD. Data from 201 parent interviews and 189 adolescent interviews were examined. Four potential factor structures for the 18 ADHD symptoms were tested using confirmatory factor analysis: two models with correlated factors and two bifactor models. A bifactor model with two specific factors best accounted for adolescent symptoms, according to both parent and adolescents’ reports. Replication of these findings from behavioral rating scales completed for this sample by parents and teachers indicates that the findings are not method– or informant-specific. The results suggest that there is an important unitary component to ADHD symptoms and separable dimensional traits of Inattention and Hyperactivity/Impulsivity.     

Sluggish Cognitive Tempo in Psychiatrically Hospitalized Children: Factor Structure and Relations to Internalizing Symptoms, Social Problems, and Observed Behavioral Dysregulation

As research examining sluggish cognitive tempo (SCT) advances, it is important to examine the structure and validity of SCT in a variety of samples, including samples of children who are clinically-distressed but not referred specifically for attention-deficit/hyperactivity disorder (ADHD). The present study used a large sample of psychiatrically hospitalized children (N?=?680; 73 % male; 66 % African American) between the ages of 6 and 12 to examine the latent structure of SCT, ADHD, oppositional defiant disorder (ODD), depression, and anxiety using confirmatory factor analysis (CFA). Results of the CFA analyses demonstrated that SCT is distinct from these other dimensions of child psychopathology, including ADHD inattention, depression, and anxiety. Regression analyses indicated that SCT symptoms were positively associated with depression and, to a lesser degree, anxiety. SCT symptoms were also positively associated with children’s general social problems, whereas SCT symptoms were negatively associated with an observational measure of behavioral dysregulation (i.e., frequency of time-outs received as a part of a manualized behavior modification program). These associations were significant above and beyond relevant child demographic variables (i.e., age, sex, race), children’s other mental health symptoms (i.e., ADHD, ODD, depression, anxiety symptoms), and, for all relations except child anxiety, parents’ own anxiety and depression symptoms.     

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.