Gender Differences in the Comorbidity of ADHD Symptoms and Specific Learning Disorders in a Population-Based Sample

Children with attention deficit hyperactivity disorder (ADHD) often exhibit comorbid specific learning disorders. In clinical samples, comorbidity in girls with ADHD tends to be more common than in boys with ADHD. However, this is not the case in studies of random samples. In this paper gender differences in the comorbidity of ADHD symptoms and learning disorders in reading, spelling and math are explored in a population-based sample of 2605 3rd and 4th graders (1304 girls) without symptoms of ADHD and 415 (141 girls) with symptoms of ADHD. Girls with ADHD symptoms had higher ratios of comorbid math disorders than boys with ADHD symptoms, but not with reading or spelling disorders. Math achievement was predicted by gender and by symptoms of inattention. Girls with ADHD symptoms and math disorders received the same amount of additional support from teachers or therapists as boys with ADHD symptoms and math disorders. Our results highlight the importance of exploring the increased comorbidity of specific learning disorders in children with ADHD symptoms and especially with math disorders in girls with ADHD symptoms. Implications for providing suitable interventions and preventing the accumulation of academic problems are discussed.

Sex Effects on Mirror Overflow during Finger Tapping in Children with ADHD

Objectives: The presence of excessive mirror overflow in children with Attention Deficit/Hyperactivity Disorder (ADHD) is discussed in numerous published reports. These reports, however, include a limited age range in their samples. The objective of this study is to examine the effects of diagnosis and sex on mirror overflow and standard deviation (SD) of tap time in children with and without ADHD across a larger age range (5–12 years) of children. Methods: One-hundred and forty-eight children with ADHD and 112 age- and sex-matched typically developing (TD) children completed a finger sequencing task. Mirror overflow, SD of tap time, and mean tap time were measured using finger twitch transducers. Results: Results reveal a significant diagnostic effect on mirror overflow such that boys and girls with ADHD demonstrate increased overflow compared to same-sex TD children. Boys with ADHD demonstrated more variable tap times compared to TD boys; no diagnostic effect was observed in the girls. Conclusions: Boys with ADHD exhibit anomalous motor variability; girls with ADHD show similar levels of variability as TD girls. Boys and girls with ADHD exhibit similar levels of excessive mirror overflow. This lack of sex differences on mirror overflow is distinct from reports finding sex effects on overflow and could result from an examination of a broader age range than is included in prior reports. Adolescent data would provide a greater understanding of the trajectory of anomalous mirror overflow across development. Examination of functional and structural connectivity would expand the current understanding of the neurobiological foundation of motor overflow.

Friendships of Adolescents With Attention-Deficit/Hyperactivity Disorder

The purpose of this study was to determine whether adolescents with and without attention-deficit/hyperactivity disorder (ADHD) differ regarding their friendships. The sample comprised 107 adolescents (59 ADHD, 48 typically developing comparison), ages 13 to 18 years. Adolescents and their parents completed questionnaires that measured the number and duration of the adolescents’ friendships, the frequency of contact they had with their friends, and the characteristics of their friends. Adolescents with and without ADHD did not differ in the number of friends they nominated, the duration of their friendships, and the frequency of contact with friends. Adolescents with ADHD were more likely to have friends who were younger or older by two or more years and close friends with behavior problems than comparison adolescents. Girls with ADHD had fewer of their friendships corroborated by parents than girls without ADHD, and fewer of their best friends attending their school. Only girls with ADHD had friends whom they initially met online.

Meta-Analysis of Sex Differences in ADHD Symptoms and Associated Cognitive Deficits

Objective: A meta-analysis was carried out to determine whether there are sex differences among children and adolescents with ADHD on the primary symptoms of ADHD and on executive and attentional functioning. Method: Studies published from 1997 to 2017 comparing boys and girls with a valid ADHD diagnosis were retained. Results: The meta-analysis found boys with ADHD to be more hyperactive than girls with ADHD and boys to have more difficulties in terms of motor response inhibition and cognitive flexibility. Results also confirm that youths with ADHD have more executive deficits than non-ADHD peers have, but there is no sex difference in this regard. Conclusion: Results show that there are sex differences in the behavioral expression of the difficulties related to ADHD. This highlights the importance of pursuing research to refine the profile of girls with ADHD and to develop diagnostic criteria adapted to each sex.