Absence of gender effects on attention deficit hyperactivity disorder: findings in nonreferred subjects

Attention-deficit/hyperactivity disorder associated with KChIP1 rs1541665 in Kv channels accessory proteins

Attention-deficit/hyperactivity disorder (ADHD) is an early onset childhood neurodevelopmental disorder with high heritability. A number of genetic risk factors and environment factors have been implicated in the pathogenesis of ADHD. Genes encoding for subtypes of voltage-dependent K channels (Kv) and accessory proteins to these channels have been identified in genome-wide association studies (GWAS) of ADHD. We conducted a two-stage case–control study to investigate the associations between five key genes (KChIP4, KChIP1, DPP10, FHIT, and KCNC1) and the risk of developing ADHD. In the discovery stage comprising 256 cases and 372 controls, KChIP1 rs1541665 and FHIT rs3772475 were identified; they were further genotyped in the validation stage containing 328cases and 431 controls.KChIP1 rs1541665 showed significant association with a risk of ADHD at both stages, with CC vs TT odds ratio (OR) = 1.961, 95% confidence interval (CI) = 1.366–2.497, in combined analyses (P-FDR = 0.007). Moreover, we also found rs1541665 involvement in ADHD-I subtype (OR (95% CI) = 2.341(1.713, 3.282), and Hyperactive index score (P = 0.005) in combined samples.Intriguingly, gene-environmental interactions analysis consistently revealed the potential interactionsof rs1541665 collaboratingwith maternal stress pregnancy (P_mul = 0.021) and blood lead (P_add = 0.017) to modify ADHD risk. In conclusion, the current study provides evidence that genetic variants of Kv accessory proteins may contribute to the susceptibility of ADHD.Further studies with different ethnicitiesare warranted to produce definitive conclusions.

False Memory in Adults With ADHD: A Comparison Between Subtypes and Normal Controls

OBJECTIVES

To examine the performance on the Deese-Roediger-McDermott task of adults divided into ADHD subtypes and compares their performance to that of healthy controls to examine whether adults with ADHD are more susceptible to the production of false memories under experimental conditions.

METHOD

A total of 128 adults with ADHD (50% females), classified into three Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV-TR) subtypes, were compared with 48 controls.

RESULTS

The results indicated that the ADHD participants recalled and recognized fewer studied words than the controls, the ADHD groups produced more false memories than the control group, no differences in either the false positives or the false negatives. The ADHD-combined (ADHD-CT) group recognized significantly more critical words than the control, ADHD-predominantly inattentive (ADHD-IA), and ADHD-predominantly hyperactive-impulsive (ADHD-HI) groups. The ADHD groups recalled and recognized more false positives, were more confident in their false responses, and displayed more knowledge corruption than the controls. The ADHD-CT group recalled and recognized more false positives than the other ADHD groups.

CONCLUSION

The adults with ADHD have more false memories than the controls and that false memory formation varied with the ADHD subtypes.

Risk of unintentional injuries in children and adolescents with ADHD and the impact of ADHD medications: protocol for a systematic review and meta-analysis

INTRODUCTION

Attention-deficit hyperactivity disorder (ADHD) has been related to increased rates of unintentional injuries. However, the magnitude of the effect and to which extent variables such as sex, age or comorbidity can influence this relationship is unknown. Additionally, and importantly, it is unclear if, and to which degree, ADHD medications can decrease the number of unintentional injuries. Due to the amount of economic and social resources invested in the treatment of injuries, filling these gaps in the literature is highly relevant from a public health standpoint. Here, we present a protocol for a systematic review and meta-analysis to estimate the relationship between ADHD and unintentional injuries and assess the impact of pharmacological treatment for ADHD METHODS AND ANALYSIS: We will combine results from 114 bibliographic databases for studies relating ADHD and risk of injuries. Bibliographic searches and data extraction will be carried out independently by two researchers. The studies' risk of bias will be assessed using the Newcastle-Ottawa Scale. Articles reporting ORs or HRs of suffering an injury in ADHD compared with controls (or enough data to calculate them) will be combined using Robust Variance Estimation, a method that permits to include multiple non-independent outcomes in the analysis. All analyses will be carried out in Stata. Age, sex and comorbid conduct disorders will be considered as potential causes of variance and their effect analysed through meta-regression and subgroup analysis. Sensitivity analyses will exclude articles with longer follow-ups, non-stringent definitions of ADHD or controls and statistically uncontrolled/controlled outcomes. Studies implementing a self-controlled case series methodology to investigate if ADHD drugs reduce the risk of injuries will be combined with a generalised linear mixed model using the Poisson distribution and a log link function.

REGISTRATION DETAILS

PROSPERO-Prospective Register of Systematic Reviews (CRD42017064967).

Greater delay discounting among girls, but not boys, with ADHD correlates with cognitive control

Cognitive neuroscience models suggest both reward valuation and cognitive control contribute to reward-based decision-making. The current study examined the relationship between cognitive control and delay discounting (i.e., choosing smaller, immediate over larger, delayed rewards) in a large sample of boys and girls diagnosed with attention-deficit/hyperactivity disorder (ADHD; N = 95) and typically developing control children (TD; N = 59). Specifically, we examined performance on multiple measures of cognitive control (i.e., Go/No-Go task, Stop Signal task, and Spatial Span task) and delay discounting (i.e., Classic Delay Discounting and Real-Time Delay Discounting tasks), as well as the relationship between these measures. Results indicated that sex moderated the effects of group on task performance. Specifically, girls with ADHD, but not boys with the disorder, exhibited atypical delay discounting of real-time rewards. Results from correlational analyses indicated that delay discounting and cognitive control were not significantly correlated in the overall sample. Multiple regression analyses demonstrated that among girls with ADHD poorer spatial working memory and inhibitory control predicted greater real-time discounting. Collectively, findings provide support for distinct patterns of cognitive control and delay discounting among school-aged girls and boys with ADHD. Additionally, findings suggest that among girls with ADHD, those who exhibit relatively poor working memory and inhibitory control might be a particularly vulnerable subgroup with the greatest propensity to exhibit maladaptive decision-making.

Protective effect or missed diagnosis? Females with autism spectrum disorder

Autism spectrum disorder (ASD) has historically been diagnosed more frequently in males than females. One explanation for this is the ‘female protective effect’: that there is something inherent in being female that makes girls and women less susceptible to ASD. Another possibility is that ASD is under-diagnosed in girls and women, due to the existence of a ‘female autism phenotype’, which is not well captured by current, male-biased diagnostic criteria. To evaluate the ‘female protective effect’ and ‘female autism phenotype’ hypotheses, this narrative review describes recent developments exploring the genetic underpinning and behavioral expression of ASD in females. We then look at the ways to better identify females with ASD who may be missed under the current diagnostic criteria.

Gender Moderates Association Between Emotional-Behavioral Problems and Text Comprehension in Children with Both Reading Difficulties and Adhd

Evidence suggests that higher order linguistic functioning such as text comprehension is particularly vulnerable to emotional modulation. Gender has been identified as an important moderating variable in emotional expression such that girls tend toward internalizing emotions (e.g., sadness, anxiety) whereas boys tend toward externalizing emotions (e.g., anger, combativeness), which may influence the relationship between emotion and text comprehension. The present study examined whether gender moderates the relationship between emotional-behavioral problems and text comprehension among children (n = 187; boys= 115, girls = 72) with both word reading difficulties (RD) and attention-deficit/hyperactivity disorder (ADHD), a sample widely acknowledged to be at increased risk for developing emotional-behavioral problems such as anxiety, poor academic self-concept, and delinquency. A moderated regression analysis tested for the significance of two separate interaction terms (i.e., gender × externalizing problems, gender × internalizing problems) after controlling for gender, IQ, basic reading skills, cognitive-linguistic processes closely related to reading, attentional problems, internalizing problems, and externalizing problems. Results indicated that gender significantly and uniquely moderates the relationship between emotional-behavioral problems and text comprehension. Specifically, text comprehension was relatively lower among girls with relatively higher externalizing problems, whereas no such association was observed among boys. These results contribute to our understanding of cognition-emotion interactions within reading development and raise important implications.

SLC6A1 gene involvement in susceptibility to attention-deficit/hyperactivity disorder: A case-control study and gene-environment interaction

Attention-deficit/hyperactivity disorder (ADHD) is an early onset childhood neurodevelopmental disorder with an estimated heritability of approximately 76%. We conducted a case-control study to explore the role of the SLC6A1 gene in ADHD. The genotypes of eight variants were determined using Sequenom MassARRAY technology. The participants in the study were 302 children with ADHD and 411 controls. ADHD symptoms were assessed using the Conners Parent Symptom Questionnaire. In our study, rs2944366 was consistently shown to be associated with the ADHD risk in the dominant model (odds ratio [OR]=0.554, 95% confidence interval [CI]=0.404-0.760), and nominally associated with Hyperactive index score (P=0.027). In addition, rs1170695 has been found to be associated with the ADHD risk in the addictive model (OR=1.457, 95%CI=1.173-1.809), while rs9990174 was associated with the Hyperactive index score (P=0.010). Intriguingly, gene-environmental interactions analysis consistently revealed the potential interactions of rs1170695 with blood lead (P_mul=0.044) to modify the ADHD risk. Expression quantitative trait loci analysis suggested that these positive single nucleotide polymorphisms (SNPs) may mediate SLC6A1 gene expression. Therefore, our results suggest that selected SLC6A1 gene variants may have a significant effect on the ADHD risk.

Co-Occurrence of ODD and CD in Preschool Children With Symptoms of ADHD

OBJECTIVE

Patterns of co-occurrence between ADHD, Oppositional Defiant Disorder (ODD), and Conduct Disorder (CD) were examined in a sample of non-referred preschool children. ADHD subtypes and sex differences were also explored.

METHOD

Children aged 3.5 years ( n = 1,048) with high scores on ADHD characteristics were recruited from the Norwegian Mother and Child Cohort Study and clinically assessed, including a semi-structured psychiatric interview.

RESULTS

In children with ADHD, concurrent ODD was present more often than CD (31% vs. 10%), but having ADHD gave higher increase in the odds of CD than of ODD (ODD: odds ratio [OR] = 6.7, 95% confidence interval [CI] = [4.2, 10.8]; CD: OR = 17.6, 95% CI = [5.9, 52.9]). We found a greater proportion of children having the combined ADHD subtype as well as more severe inattentiveness among children with co-occurring CD compared with ODD. Sex differences were minor.

CONCLUSION

There are important differences in co-occurring patterns of ODD and CD in preschool children with ADHD.

Sex Differences in the Physiological and Behavioral Effects of Chronic Oral Methylphenidate Treatment in Rats

Methylphenidate (MP) is a psychostimulant prescribed for Attention Deficit Hyperactivity Disorder. Previously, we developed a dual bottle 8-h-limited-access-drinking-paradigm for oral MP treatment of rats that mimics the pharmacokinetic profile of treated patients. This study assessed sex differences in response to this treatment. Male and female Sprague Dawley rats were assigned to one of three treatment groups at 4 weeks of age (n = 12/group): Control (water), low dose (LD) MP, and high dose (HD) MP. Rats drank 4 mg/kg MP (LD) or 30 mg/kg MP (HD) during the first hour, and 10 mg/kg (LD) or 60 mg/kg MP (HD) for the remaining 7 h each day. Throughout 3 months of treatment, rats were monitored for body weight, food intake, and fluid intake; as well as tested for open field behavior, circadian activity, novel object recognition, and social interaction. Chronic MP treated rats exhibited reduced fluid intake during distinct treatment weeks to a greater extent in males, and reduced total fluid intake in males only. HD MP treatment decreased body weight in both sexes, while HD MP increased total food intake in females only, likely to offset energy deficits resulting from MP-induced hyperactivity. LD and HD MP increased locomotor activity in the open field, particularly in females and during later treatment weeks. MP dose-dependently increased activity during the dark cycle of circadian testing in females, while in males hyperactivity was only exhibited by HD rats. HD MP increased center activity to a greater extent in males, while MP increased rearing behavior in females only. MP had no effect on social behavior or novel object recognition in either sex. This study concludes that chronic oral MP treatment at clinically-relevant dosages has significant effects on food intake, body weight, open field behavior, and wake cycle activity. Particularly marked sex differences were apparent for locomotor activity, with females being significantly more sensitive to the hyperactivating effects of the drug. These findings suggest that chronic MP exposure beginning in adolescence can have significant behavioral effects that are both dose- and sex-dependent, and raise concerns regarding the reversibility of these effects post-discontinuation of treatment.

Screening for Adult Attention-Deficit/Hyperactivity Disorder in a Psychiatric Outpatient Population with Specific Focus on Sex Differences

BACKGROUND/AIMS

Attention-deficit/hyperactivity disorder (ADHD) is often overlooked in adults; moreover, the problem seems to be even more critical in women. In the present, observational screening study, a clinical, particularly adult outpatient population was examined regarding frequency and severity of a likely ADHD, whereby sex differences were of particular interest.

METHODS

224 participants, 146 men and 78 women, were included. Based on data recorded with the self-rating WHO screening instrument Adult ADHD Self-Report Scale (ASRS-v1.1), it was examined how many participants were conspicuous for adult ADHD by exceeding a predefined cutoff value (COV) (COV ≥ 4 for ASRS-6, and ≥12 for ASRS-18). To examine frequency distributions, χ² tests were conducted. For the inferential statistical comparison of means, t-tests for independent samples or Mann-Whitney U tests were calculated.

RESULTS

34.4% of the sample was screened positive in the ASRS-v1.1 screener short version, ASRS-6, while 17.4% were conspicuous in the symptom checklist, ASRS-18. There were indeed more men screened positive, but the difference in the frequency between the sexes was not statistically significant, indicating a balanced sex ratio. Further, severity of ADHD core symptoms inattention and hyperactivity/impulsivity was examined by comparing ASRS-18 symptom subscale scores. In concordance with the hypothesis, men and women did not differ in severity of symptoms.

CONCLUSION

Results indicate that women might be affected by ADHD in a comparable manner as men; this emphasizes the importance for the awareness of ADHD in both sexes in clinical practice.

The Effects of Perinatal Oxycodone Exposure on Behavioral Outcome in a Rodent Model

Opiate addiction is now a major public health problem. Perinatal insults and exposure to opiates such as morphine in utero are well known to affect development of the hypothalamic-pituitary-adrenal axis of the offspring adversely and are associated with a higher risk of developing neurobehavioral problems. Oxycodone is now one of the most frequently abused pain killers during pregnancy; however, limited data are available regarding whether and how perinatal oxycodone exposure (POE) alters neurobehavioral outcomes of the offspring. We demonstrated that exposure to 0.5 mg/kg/day oxycodone in utero was associated with hyperactivity in adult rats in an open field. No significant effects of POE were detected on isolation-induced ultrasonic vocalizations in the early postnatal period or on learning and memory in the water maze in adult offspring. Our findings are consistent with hyperactivity problems identified in children exposed to opiates in utero.

Subthreshold and threshold attention deficit hyperactivity disorder symptoms in childhood: psychosocial outcomes in adolescence in boys and girls

OBJECTIVE

To examine the association between different levels of childhood attention deficit hyperactivity disorder (ADHD) symptoms and sex differences in psychosocial outcomes during adolescence.

METHOD

Swedish children (n = 4635) were screened for neuropsychiatric symptoms at age 9 or 12. ADHD symptoms were divided into three levels: screen-negative, screen-intermediate, and screen-positive. At follow-up (age 15), parents and teenagers filled out questionnaires regarding (i) hyperactivity/inattention, (ii) peer problems, (iii) school problems, (iv) internalizing problems, (v) antisocial behaviour, (vi) alcohol misuse, and (vii) drug misuse. All outcomes were controlled for symptoms of diagnostic categories other than ADHD.

RESULTS

Increasing levels of ADHD symptoms in childhood were associated with higher proportions of adolescents who displayed negative psychosocial outcomes. More girls than boys reported internalizing problems (all levels) and risky drug use (screen-intermediate and screen-positive only). More boys reported antisocial behaviour at the screen-negative and screen-intermediate levels, but at the screen-positive level, similar proportions of girls and boys displayed antisocial behaviour.

CONCLUSION

The findings support the view that ADHD symptoms, as well as their negative outcomes, are dimensionally distributed in the population and that adolescent girls and boys display different risk profiles. The findings confirm that ADHD symptoms are associated with higher risk of drug misuse in girls.

[Effects of Cognitive Behavioral Therapy on Attention Deficit Hyperactivity Disorder among School-aged Children in Korea: A Meta-Analysis]

PURPOSE

This study was a meta-analysis designed to identify effects of Cognitive Behavioral Therapy (CBT) interventions in alleviating main symptoms of Attention Deficit Hyperactivity Disorder (ADHD) among school-aged children in Korea.

METHODS

Examination of several databases including Research Information Sharing Service, Korean Studies Information Service System, Data Base Periodical Information Academic and hand-searched article references, resulted in identification of 1,298 studies done between 2000 and 2013 of which 21 met the inclusion criteria. Comprehensive Meta-Analysis version 2.0 was used to analyze effect sizes, explore possible causes of heterogeneity, and check publication bias with a funnel plot and its trim-and-fill analysis.

RESULTS

Overall effect size of CBT intervention was large (g=1.08) along with each outcome of self-control (g=1.26), lack of attention (g=1.02), social skills (g=0.92), and hyperactivity (g=0.92). For heterogeneity, moderator analysis was performed, but no significant differences were found between the RCT (Randomized Controlled Trials) group and the NRCT (Non RCT) group. Also, meta-regression was performed using sample size, number of sessions, and length of session as predictors, but no statistically significant moderators were found. Finally, a funnel plot along with trim-and-fill analysis was produced to check for publication bias, but no significant bias was detected.

CONCLUSION

Based on these findings, there is clear evidence that CBT intervention has significant positive effects on the main symptoms of school-aged children suffering ADHD. Further research is needed to target diverse age groups with ADHD along with more RCT studies to improve the effectiveness of the CBT intervention.

Early severe institutional deprivation is associated with a persistent variant of adult attention-deficit/hyperactivity disorder: clinical presentation, developmental continuities and life circumstances in the English and Romanian Adoptees study

BACKGROUND

Early-life institutional deprivation is associated with attention-deficit/hyperactivity disorder (ADHD) later in childhood and adolescence. In this article, we examine, for the first time, the persistence of deprivation-related ADHD into young adulthood in a sample of individuals adopted as young children by UK families after periods in extremely depriving Romanian orphanages.

METHODS

We estimated rates of ADHD at age 15 years and in young adulthood (ages 22-25 years) in individuals at low (LoDep; nondeprived UK adoptees and Romanian adoptees with less than 6-month institutional exposure) and high deprivation-related risk (HiDep; Romanian adoptees with more than 6-month exposure). Estimates were based on parent report using DSM-5 childhood symptom and impairment criteria. At age 15, data were available for 108 LoDep and 86 HiDep cases, while in young adulthood, the numbers were 83 and 60, respectively. Data on education and employment status, IQ, co-occurring symptoms of young adult disinhibited social engagement (DSE), autism spectrum disorder (ASD), cognitive impairment, conduct disorder (CD), callous-unemotional (CU) traits, anxiety, depression and quality of life (QoL) were also collected.

RESULTS

ADHD rates in the LoDep group were similar to the general population in adolescence (5.6%) and adulthood (3.8%). HiDep individuals were, respectively, nearly four (19%) and over seven (29.3%) times more likely to meet criteria, than LoDep. Nine 'onset' young adult cases emerged, but these had a prior childhood history of elevated ADHD behaviours at ages 6, 11 and 15 years. Young adult ADHD was equally common in males and females, was predominantly inattentive in presentation and co-occurred with high levels of ASD, DSE and CU features. ADHD was associated with high unemployment and low educational attainment.

CONCLUSION

We provide the first evidence of a strong persistence into adulthood of a distinctively complex and impairing deprivation-related variant of ADHD. Our results confirm the powerful association of early experience with later development in a way that suggests a role for deep-seated alterations to brain structure and function.

Health, Dietary Habits, and Achievement Motivation in College Students With Self-Reported ADHD Diagnosis

OBJECTIVE

The present study aimed to investigate aspects of health and motivation in a subpopulation of college students with ADHD.

METHOD

Seventy-seven college students with self-reported ADHD (49 women; M age = 25.82, SD = 4.62) and 120 college students without ADHD (65 women; M age = 25.17, SD = 5.41) participated in an online survey assessing their health, dietary habits, and achievement motivation.

RESULTS

College students with ADHD showed impairment in psychological functioning, impairment in their mental health, and reported more ambition and less self-control. Furthermore, we found gender differences: Women with ADHD reported worse psychological functioning, and the gender differences in obsessive-compulsive behavior and compensatory effort were mediated by the timing of diagnosis.

CONCLUSION

College students, especially women, with ADHD struggle with health-related issues. Some of these gender differences might be due to under diagnosis of girls in childhood. Differences in achievement motivation might indicate compensatory mechanisms.

Association Between Pubertal Onset and Symptoms of ADHD in Female University Students

OBJECTIVE

This exploratory study investigated how the timing of female pubertal maturation was associated with the symptoms of ADHD in a non-clinical female undergraduate sample (N = 253).

METHOD

Participants (Mage = 20.2 ± 1.7 years) completed a set of self-report rating scales examining pubertal onset and ADHD symptoms and related deficits.

RESULTS

Logistic regression analysis indicated that early puberty was associated with elevation in symptoms, including difficulties in attention (odds ratio [OR] = 1.270, p = .019), emotion regulation (OR = 1.070, p = .038), and more risky behavior (OR = 1.035, p = .045). That is, increased symptom endorsement was shown to significantly help classify those who reported having an earlier pubertal onset relative to their peers.

CONCLUSION

Findings highlight the potential role of sex hormones during puberty in explaining the gender differences in prevalence rates of ADHD and symptom profiles.

Associations between neurodevelopmental disorders and factors related to school, health, and social interaction in schoolchildren: Results from a Swedish population-based survey

BACKGROUND

Children and adolescents with autism spectrum disorder (ASD) or attention-deficit/hyperactivity disorder (ADHD) are more likely to be surrounded by different risk factors. In order to work preventively with decreasing ADHD and ASD symptoms, there is a need of more knowledge concerning risk factors.

OBJECTIVE

This study aimed to investigate school, health, lifestyle and social interactions association with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) among schoolchildren aged 6-17 years.

METHODS

Data for 18,416 children and adolescents aged 6-17 years in the county of Värmland, Sweden, from the school year 2012/2013 and 2013/2014 were obtained from the Student Health Database, which includes information on health examinations by school nurses and self-reported information of mental and physical health, social relations, physical activity, and school conditions.

RESULTS

Of all participants, 2.4% reported only ADHD and 1.6% reported only ASD. The results confirmed that ADHD or ASD was significantly associated with worse school experiences, lower socioeconomic status, less physical activity, more substance use, weaker social network and more impairments than those without ADHD or ASD.

CONCLUSIONS

Knowledge of risk or protective factors during school years is needed to develop interventions to reduce symptoms of neurodevelopmental disorders in children and adolescents.

Is hyperactivity ubiquitous in ADHD or dependent on environmental demands? Evidence from meta-analysis

Hyperactivity, or excess gross motor activity, is considered a core and ubiquitous characteristic of ADHD. Alternate models question this premise, and propose that hyperactive behavior reflects, to a large extent, purposeful behavior to cope with environmental demands that interact with underlying neurobiological vulnerabilities. The present review critically evaluates the ubiquity and environmental modifiability of hyperactivity in ADHD through meta-analysis of 63 studies of mechanically measured activity level in children, adolescents, and adults with ADHD relative to typically developing groups. Random effects models corrected for publication bias confirmed elevated gross motor activity in ADHD (d=0.86); surprisingly, neither participant age (child vs. adult) nor the proportion of each ADHD sample diagnosed with the inattentive subtype/presentation moderated this effect. In contrast, activity level assessed during high cognitive load conditions in general (d=1.14) and high executive functioning demands in particular (d=1.39) revealed significantly higher effect sizes than activity level during low cognitive load (d=0.36) and in-class schoolwork (d=0.50) settings. Low stimulation environments, more rigorous diagnostic practices, actigraph measurement of movement frequency and intensity, and ADHD samples that included fewer females were also associated with larger effects. Overall, the results are inconsistent with DSM-5 and ADHD models that a) describe hyperactivity as ubiquitous behavior, b) predict a developmental decline in hyperactivity, or c) differentiate subtypes/presentations according to perceived differences in hyperactive behavior. Instead, results suggest that the presence and magnitude of hyperactive behavior in ADHD may be influenced to a considerable extent by environmental factors in general, and cognitive/executive functioning demands in particular.

Attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder with a prevalence of 1·4-3·0%. It is more common in boys than girls. Comorbidity with childhood-onset neurodevelopmental disorders and psychiatric disorders is substantial. ADHD is highly heritable and multifactorial; multiple genes and non-inherited factors contribute to the disorder. Prenatal and perinatal factors have been implicated as risks, but definite causes remain unknown. Most guidelines recommend a stepwise approach to treatment, beginning with non-drug interventions and then moving to pharmacological treatment in those most severely affected. Randomised controlled trials show short-term benefits of stimulant medication and atomoxetine. Meta-analyses of blinded trials of non-drug treatments have not yet proven the efficacy of such interventions. Longitudinal studies of ADHD show heightened risk of multiple mental health and social difficulties as well as premature mortality in adult life.

Attention Deficit/Hyperactivity Disorder and Urinary Nonylphenol Levels: A Case-Control Study in Taiwanese Children

Objective

Nonylphenol (NP) belongs to the family of endocrine disruptors, and it is widely used in industrial applications and is ubiquitous in daily foods. Animal studies have suggested that NP exposure might promote motor hyperactivity, likely by causing deficits in dopaminergic neurons. However, research assessing NP exposure and epidemiology studies on human populations are limited. The aim of this study was to explore the association between child NP exposure and ADHD while considering particular covariants, such as lead levels and dopamine-related gene variations.

Methods

A case-control study was conducted on patients with clinically diagnosed ADHD; the Swanson, Nolan and Pelham, Fourth Revision (SNAP-IV) questionnaire was used to identify normal controls aged 4–15 years. Participants were examined for urinary NP concentrations, blood lead levels, and select single-nucleotide polymorphisms of two dopamine-related genes (D4 dopamine receptor, DRD4, and dopamine transporter, DAT1). Socio-demographic variables, maternal lifestyle factors during pregnancy and family medical history were obtained using a questionnaire.

Results

A total of 97 children with doctor-diagnosed ADHD and 110 normal controls were enrolled. The blood lead levels in both groups were similar (1.57±0.73 vs. 1.73±0.77 μg/dL, p = 0.15). No significant difference in urinary NP concentration was found between the children with ADHD and the control subjects (4.52±3.22 μg/g cr. vs. 4.64±2.95 μg/g cr., p = 0.43). ADHD was significantly more prevalent among males in this study (male to female ratio: 5:1 for the ADHD group and 1.3:1 for the control group, p<0.01). The analysis was repeated after excluding the females, but this had no effect on the association between NP and ADHD. The regression model, including or excluding females, indicated no increased odds of having ADHD in the context of NP exposure after adjusting for covariants.

Conclusion

This study indicated that NP exposure might not promote ADHD in children, even though children in Taiwan had relatively high levels of NP compared to those reported previously and those in developed nations.

Sex Differences in Attentional Performance in a Clinical Sample With ADHD of the Combined Subtype

OBJECTIVE

The goal of the present study was to assess whether girls with ADHD express similar deficits in various attention tasks to those described in boys.

METHOD

A total of 175 children with the combined subtype of ADHD (89 females) and 132 normal controls (60 females) aged 8 to 14 years participated. Five different tests were conducted: alertness, sustained attention, focused attention, divided attention, and a set-shifting task.

RESULTS

The children with ADHD performed worse on all aspects of attention compared with healthy control participants. Several overall general sex differences could be detected, with boys exhibiting faster reaction times and greater response variability. Controlling for ADHD symptom severity and psychiatric comorbidities, no Sex × Diagnosis interaction was found, suggesting that males and females with ADHD experience comparable attentional deficits.

CONCLUSION

These results indicate that deficits in various attentional domains are a robust component of ADHD in males and females.

Longitudinal relations among inattention, working memory, and academic achievement: testing mediation and the moderating role of gender

Introduction. Behavioral inattention, working memory (WM), and academic achievement share significant variance, but the direction of relationships across development is unknown. The aim of the present study was to determine whether WM mediates the pathway between inattentive behaviour and subsequent academic outcomes. Methods. 204 students from grades 1-4 (49.5% female) were recruited from elementary schools. Participants received assessments of WM and achievement at baseline and one year later. WM measures included a visual-spatial storage task and auditory-verbal storage and manipulation tasks. Teachers completed the SWAN behaviour rating scale both years. Mediation analysis with PROCESS (Hayes, 2013) was used to determine mediation pathways. Results. Teacher-rated inattention indirectly influenced math addition fluency, subtraction fluency and calculation scores through its effect on visual-spatial WM, only for boys. There was a direct relationship between inattention and math outcomes one year later for girls and boys. Children who displayed better attention had higher WM scores, and children with higher WM scores had stronger scores on math outcomes. Bias-corrected bootstrap confidence intervals for the indirect effects were entirely below zero for boys, for the three math outcomes. WM did not mediate the direct relationship between inattention and reading scores. Discussion. Findings identify inattention and WM as longitudinal predictors for math addition and subtraction fluency and math calculation outcomes one year later, with visual-spatial WM as a significant mediator for boys. Results highlight the close relationship between inattention and WM and their importance in the development of math skills.

Gender differences in adults with attention-deficit/hyperactivity disorder: A narrative review

Certain characteristics of attention-deficit/hyperactivity disorder (ADHD) in children have long been known to differ by gender. What has not been as widely studied is whether gender is similarly associated with ADHD differences in adults. In this review, the relation between gender and adult ADHD prevalence, persistence, impairment, comorbidity, cognitive functioning, and treatment response was examined across 73 studies. Although gender was related to several characteristics and correlates of adult ADHD, it appeared that many of these gender differences may be at least be partially attributed to methodological artifacts or social and cultural influences, rather than fundamental differences in the expression of ADHD in men and women. We highlight how understanding the nature of the relation between gender and ADHD across the lifespan is complicated by a number of methodological difficulties, and offer recommendations for how emerging research and clinical practice can better incorporate gender into the conceptualization of ADHD in adulthood.

[Has the prevalence of parent-reported diagnosis of attention deficit hyperactivity disorder (ADHD) in Germany increased between 2003-2006 and 2009-2012? Results of the KiGGS-study: first follow-up (KiGGS Wave 1)]

Recent international studies have reported a considerable increase in the diagnosis of attention deficit hyperactivity disorder (ADHD). Data from German statutory health insurance companies suggest a comparable trend for Germany. Based on data from the nationally representative study KiGGS Wave 1 (2009-2012) it was the aim of this study to report on the prevalence rates of parent-reported ADHD diagnoses in children and adolescents aged 3-17 years as well as to report on time trends in comparison with the KiGGS baseline study (2003-2006). ADHD caseness was met if a parent reported that a physician or a psychologist diagnosed their child with ADHD. Participants without a reported ADHD diagnosis but who scored ≥ 7 (clinical range) on the parent-rated hyperactivity subscale of the Strengths and Difficulties Questionnaire (SDQ) were considered as potential ADHD cases. The prevalence of diagnosed ADHD was 5.0% (prevalence of potential ADHD cases 6.0%). An ADHD diagnosis was more than four and a half times more likely to be reported among boys than girls. Children from families with low socioeconomic status (SES) were more than two and a half times more likely to be diagnosed with ADHD than children from families with high SES. Among potential cases, boys were twice as common as girls, and children from families with low SES were approximately three times more common compared with those from high SES families. The proportion of lifetime ADHD diagnoses increased with age and was highest in 11- to 17-year-olds. In every fifth child with ADHD the initial diagnosis was made by the age of 6 years and in 1 out of 11 children with ADHD the initial diagnosis was made by the age of 5 years. In total, we observed no significant changes regarding the frequency of ADHD diagnosis compared to the KiGGS baseline study. Increases reported using data from German statuary health insurance companies were not reflected in the KiGGS data.

Co-occurrence of attention-deficit hyperactivity disorder symptoms with other psychopathology in young adults: parenting style as a moderator

The extent to which parenting styles can influence secondary psychiatric symptoms among young adults with ADHD symptoms is unknown. This issue was investigated in a sample of 2284 incoming college students (male, 50.6%), who completed standardized questionnaires about adult ADHD symptoms, other DSM-IV symptoms, and their parents' parenting styles before their ages of 16. Among them, 2.8% and 22.8% were classified as having ADHD symptoms and sub-threshold ADHD symptoms, respectively. Logistic regression was used to compare the comorbid rates of psychiatric symptoms among the ADHD, sub-threshold ADHD and non-ADHD groups while multiple linear regressions were used to examine the moderating role of gender and parenting styles over the associations between ADHD and other psychiatric symptoms. Both ADHD groups were significantly more likely than other incoming students to have other DSM-IV symptoms. Parental care was negatively associated and parental overprotection/control positively associated with these psychiatric symptoms. Furthermore, significant interactions were found of parenting style with both threshold and sub-threshold ADHD in predicting wide-ranging comorbid symptoms. Specifically, the associations of ADHD with some externalizing symptoms were inversely related to level of paternal care, while associations of ADHD and sub-threshold ADHD with wide-ranging comorbid symptoms were positively related to level of maternal and paternal overprotection/control. These results suggest that parenting styles may modify the effects of ADHD on the risk of a wide range of temporally secondary DSM-IV symptoms among incoming college students, although other causal dynamics might be at work that need to be investigated in longitudinal studies.

Severity of symptoms and quality of life in medical students with ADHD

OBJECTIVE

In this study, the authors examined the severity of ADHD symptoms and related quality of life in 1st and 2nd year medical students diagnosed with ADHD.

METHOD

The sample consists of 33 preclinical medical students previously diagnosed with ADHD. The Adult ADHD Quality of Life Scale (AAQoL) and Adult ADHD Self-Reported Checklist were administered.

RESULTS

Participants' ADHD-related quality of life and life productivity were negatively correlated with the severity of their ADHD symptoms. Students receiving academic accommodations reported significantly higher ADHD symptoms. The presence of a comorbid condition contributed to significantly lower psychological health scores. Unexpectedly, women had significantly lower quality of life (AAQoL total score) and significantly lower psychological health scores than men.

CONCLUSION

Since the majority of the sample reported severe ADHD symptoms while receiving medication treatment, the authors have concluded that it is important to develop psychosocial treatments to manage the associated distress from residual symptoms in medical students with ADHD.

Sex differences in attention Deficit Hyperactivity Disorder: candidate genetic and endocrine mechanisms

Attention Deficit Hyperactivity Disorder (ADHD) is a developmental condition characterised by severe inattention, pathological impulsivity and hyperactivity; it is relatively common affecting up to 6% of children, and is associated with a risk of long-term adverse educational and social consequences. Males are considerably more likely to be diagnosed with ADHD than females; the course of the disorder and its associated co-morbidities also appear to be sensitive to sex. Here, I discuss fundamental biological (genetic and endocrine) mechanisms that have been shown to, or could theoretically, contribute towards these sexually dimorphic phenomena. Greater understanding of how and why the sexes differ with respect to ADHD vulnerability should allow us to identify and characterise novel protective and risk factors for the disorder, and should ultimately facilitate improved diagnosis, prognosis and treatment.

The association of ADHD symptoms to self-harm behaviours: a systematic PRISMA review

BACKGROUND

Self-harm is a major public health issue in young people worldwide and there are many challenges to its management and prevention. Numerous studies have indicated that ADHD is associated with completed suicides and other suicidal behaviours (i.e., suicidal attempt and ideation). However, significantly less is known about the association between ADHD and self-harm.

METHOD

This is the first review of the association between ADHD and self-harm. A systematic PRISMA review was conducted. Two internet-based bibliographic databases (Medline and CINAHL) were searched to access studies which examined to any degree the association between, specifically, ADHD and self-harm.

RESULTS

Only 15 studies were identified which investigated the association between ADHD and self-harm and found evidence to support that ADHD is a potential risk factor for self-harm.

CONCLUSION

This association raises the need for more awareness of self-harm in individuals with symptoms of ADHD.

Specificity of basic information processing and inhibitory control in attention deficit hyperactivity disorder

BACKGROUND

Both inhibitory-based executive functioning (IB-EF) and basic information processing (BIP) deficits are found in clinic-referred attention deficit hyperactivity disorder (ADHD) samples. However, it remains to be determined whether: (1) such deficits occur in non-referred samples of ADHD; (2) they are specific to ADHD; (3) the co-morbidity between ADHD and oppositional defiant disorder/conduct disorder (ODD/CD) has additive or interactive effects; and (4) IB-EF deficits are primary in ADHD or are due to BIP deficits.

METHOD

We assessed 704 subjects (age 6-12 years) from a non-referred sample using the Development and Well-Being Assessment (DAWBA) and classified them into five groups: typical developing controls (TDC; n = 378), Fear disorders (n = 90), Distress disorders (n = 57), ADHD (n = 100), ODD/CD (n = 40) and ADHD+ODD/CD (n = 39). We evaluated neurocognitive performance with a Two-Choice Reaction Time Task (2C-RT), a Conflict Control Task (CCT) and a Go/No-Go (GNG) task. We used a diffusion model (DM) to decompose BIP into processing efficiency, speed-accuracy trade-off and encoding/motor function along with variability parameters.

RESULTS

Poorer processing efficiency was found to be specific to ADHD. Faster encoding/motor function differentiated ADHD from TDC and from fear/distress whereas a more cautious (not impulsive) response style differentiated ADHD from both TDC and ODD/CD. The co-morbidity between ADHD and ODD/CD reflected only additive effects. All ADHD-related IB-EF classical effects were fully moderated by deficits in BIP.

CONCLUSIONS

Our findings challenge the IB-EF hypothesis for ADHD and underscore the importance of processing efficiency as the key specific mechanism for ADHD pathophysiology.

Innovations and recent trends in the treatment of ADHD

Initiatives to develop better-tolerated, more efficacious pharmacological agents with improved drug delivery systems have driven recent research in attention-deficit hyperactivity disorder (ADHD). While stimulants are the primary pharmacotherapy for ADHD, these drugs have a limited duration of action and a subset of patients will either fail to respond to these medications or have side effects that preclude their use. The development of atomoxetine, the first nonstimulant approved for ADHD, has been followed by additional innovative research, such as the methylphenidate transdermal system, modafinil, NRP-104 and cholinergic agents. This review highlights some of the recent trends in ADHD treatment and the current status of promising treatment options that may help to shape the future of ADHD treatment.

ADHD in girls and boys--gender differences in co-existing symptoms and executive function measures

BACKGROUND

ADHD is diagnosed and treated more often in males than in females. Research on gender differences suggests that girls may be consistently underidentified and underdiagnosed because of differences in the expression of the disorder among boys and girls. One aim of the present study was to assess in a clinical sample of medication naïve boys and girls with ADHD, whether there were significant gender x diagnosis interactions in co-existing symptom severity and executive function (EF) impairment. The second aim was to delineate specific symptom ratings and measures of EF that were most important in distinguishing ADHD from healthy controls (HC) of the same gender.

METHODS

Thirty-seven females with ADHD, 43 males with ADHD, 18 HC females and 32 HC males between 8 and 17 years were included. Co-existing symptoms were assessed with self-report scales and parent ratings. EF was assessed with parent ratings of executive skills in everyday situations (BRIEF), and neuropsychological tests. The three measurement domains (co-existing symptoms, BRIEF, neuropsychological EF tests) were investigated using analysis of variance (ANOVA) and random forest classification.

RESULTS

ANOVAs revealed only one significant diagnosis x gender interaction, with higher rates of self-reported anxiety symptoms in females with ADHD. Random forest classification indicated that co-existing symptom ratings was substantially better in distinguishing subjects with ADHD from HC in females (93% accuracy) than in males (86% accuracy). The most important distinguishing variable was self-reported anxiety in females, and parent ratings of rule breaking in males. Parent ratings of EF skills were better in distinguishing subjects with ADHD from HC in males (96% accuracy) than in females (92% accuracy). Neuropsychological EF tests had only a modest ability to categorize subjects as ADHD or HC in males (73% accuracy) and females (79% accuracy).

CONCLUSIONS

Our findings emphasize the combination of self-report and parent rating scales for the identification of different comorbid symptom expression in boys and girls already diagnosed with ADHD. Self-report scales may increase awareness of internalizing problems particularly salient in females with ADHD.

Effects of Preconceptional Ethanol Consumption on ADHD-Like Symptoms in Sprague-Dawley Rat Offsprings

Ethanol exposure during gestational period is related to growth retardation, morphological abnormality, and even in neurological abnormalities including attention deficit/hyperactivity disorder (ADHD)-like behaviors on offspring. However, relatively little is known about the effects of maternal ethanol consumption prior to conception on their offspring. In this study, we investi-gated whether maternal ethanol administration during preconceptional phase produces ADHD-like behaviors in the rat offspring. Sprague-Dawley (SD) female rats were administrated ethanol via intragastric intubation with dosing regimen of 6 g/kg daily for 10 consecutive days and treated female rats then mated with non-treated male SD rats after 8 weeks. Another group subjected to the same procedure as those conducted on ethanol treated group except the saline administration instead of ethanol. Offspring was tested for their ADHD-like behaviors using open field test, Y maze test and impulsivity test that is performed in the aversive electronic foot shock paradigm. Offspring of preconceptional ethanol treated (EtOH) group showed hyperlocomotive activity, attention deficit and impulsivity. And reduction of striatal dopamine transporter (DAT) level was observed by Western blot in the EtOH group, compared to control (Con) group, while the immunohistochemical analysis exhibited increased expression of norepinephrine transporter (NET) in the frontal cortex. These results suggest that maternal ethanol consumption in the preconceptional phase induces ADHD-like behaviors in offspring that might be related to the abnormal expression of DAT and NET in rat.

Prevalence of obesity and overweight among Chinese children with attention deficit hyperactivity disorder: a survey in Zhejiang Province, China

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is often comorbid with psychiatric and developmental disorders. This study aimed to investigate the prevalence of obesity and overweight among Chinese children with ADHD, and to explore which subtypes of the disorder may specifically be associated with obesity/overweight.

METHODS

Children meeting the DSM-IV criteria for ADHD were enrolled in the study. Weight, weight z-score, height, height z-score, BMI, and BMI z-score were used to evaluate growth status. Obesity and overweight were determined using the National Growth Reference for Chinese Children and Adolescents. Relations between the prevalence of obesity/overweight and different ADHD subtypes and pubertal development were analyzed.

RESULTS

A total of 158 children with ADHD (mean age: 9.2 years) were recruited for the study. The prevalences of obesity, overweight, and combined obesity/overweight were 12.0%, 17.1%, and 29.1%, respectively, which were significantly higher than in the general Chinese population (2.1%, 4.5%, and 6.6%, respectively). Multivariable analysis showed that the children with the combined subtype of ADHD and the onset of puberty were at a higher risk of becoming obese or overweight.

CONCLUSIONS

The prevalence of obesity in Chinese children with ADHD is higher than that of the general population. Children with the ADHD combined subtype who were at the onset of puberty were more likely to be overweight or obese.

Inattentive and hyperactive preschool-age boys have lower sympathetic and higher parasympathetic activity

The presented study aimed to clarify the relationship between the autonomic nervous system and disruptive behaviors among preschoolers. Possible gender differences in autonomic activity were also examined. A total of 88 preschool-age children were enrolled in this study. Autonomic activities were measured by power spectrum analysis of heart rate variability (HRV). The Swanson, Nolan and Pelham parents and teachers rating scale (SNAP-IV) was applied to evaluate each subject's severity of disruptive behavior. The relationship between the HRV results and the SNAP-IV was evaluated by correlation analysis, which disclosed that the scores for inattention, hyperactivity/impulsivity and oppositional defiant disorder showed a negative association with LF % and LF/HF. The above scales, except for the hyperactivity subscale, also showed a positive association with HF. On separating the two genders, only boys showed the above correlations. Preschool-age boys who show more inattentive and hyperactive features have lower sympathetic and higher parasympathetic activity.

Teachers' recognition of children with ADHD: role of subtype and gender

BACKGROUND

This study investigates the ability of primary school teachers to recognise Attention Deficit/Hyperactivity Disorder (ADHD), and the impact of subtype and child gender on recognition and proposed management.

METHOD

Primary school teachers read one of four types of vignette describing the behaviour of a 9-year-old child: either a boy or a girl with inattentive or combined subtype of ADHD. Teachers were asked about their conceptualisation of the child's difficulties and their thoughts about need for specialist referral and other interventions.

RESULTS

Of 496 teachers, 99% identified the presence of a problem. Subtype (combined) of ADHD influenced teachers' recognition of ADHD and agreement that medication might be helpful. Only 13% of teachers thought that medication might be helpful.

CONCLUSIONS

Results suggest a need for better teacher awareness about inattentive subtype of ADHD.

Conceptual structure of the symptoms of adult ADHD according to the DSM-IV and retrospective Wender-Utah criteria

OBJECTIVE

Adult Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) and retrospective childhood Wender-Utah ADHD criteria are implemented in self-report measures to assess adult ADHD and its required onset in childhood. Yet their dimensional structure and relationship to adult ADHD depressivity is still at debate. Therefore, both aspects were investigated, applying two respective German instruments (ADHD-Self-Report [ADHD-SR] and Wender Utah Rating Scale-German [WURS-G]) to two student samples.

METHOD

ADHD-SR and WURS-G dimensions were identified by nonlinear confirmatory factor analyses, and their interrelations and relationship with adult depressivity were identified by structural equation modeling.

RESULTS

Adult ADHD-SR symptoms were organized into inattention, hyperactivity, and impulsivity, and WURS-G symptoms were organized into inattention/hyperactivity, affect lability, depressivity, and conduct problems. Yet only the first two WURS factors directly affected adult ADHD facets, though childhood depressivity influenced them indirectly via adult depressivity.

CONCLUSION

Only criteria of the first two WURS factors can be considered valid childhood ADHD indicators. Thus, only they should be used as an aid in the retrospective assessment of ADHD symptoms.

Youths with ADHD with and without tic disorders: comorbid psychopathology, executive function and social adjustment

Attention deficit/hyperactivity disorder (ADHD) and tic disorders (TD) commonly co-occur. Clarifying the psychiatric comorbidities, executive functions and social adjustment difficulties in children and adolescents of ADHD with and without TD is informative to understand the developmental psychopathology and to identify their specific clinical needs. This matched case-control study compared three groups (n=40 each) of youths aged between 8 and 16 years: ADHD with co-occurring TD (ADHD+TD), ADHD without TD (ADHD-TD) and typically developing community controls. Both ADHD groups had more co-occurring oppositional defiant disorder than the control group, and the presence of TD was associated with more anxiety disorders. TD did not impose additional executive function impairments or social adjustment difficulties on ADHD. Interestingly, for youths with ADHD, the presence of TD was associated with less interpersonal difficulties at school, compared to those without TD. The potential various directions of effects from co-occurring TD should be carefully evaluated and investigated for youths with ADHD.

Gender differences in consequences of ADHD symptoms in a community-based organization for youth

Attention-Deficit/Hyperactivity Disorder (ADHD) has been linked to disruptive behavior and disciplinary consequences; however, the variables involved in this process are largely unknown. The current study examined rule-breaking behavior as a mediator of the relation between ADHD symptoms and disciplinary actions 1 year later during after-school care at a community-based organization in a sample of 147 school-age children ( M = 8.22 years; 54.4% male). Additionally, gender was examined as a moderator of these relations. Total ADHD symptoms positively predicted rule-breaking behavior at 1-year follow-up, which in turn was positively associated with disciplinary actions also at 1-year follow-up. Gender moderated these relations, such that the mediated effect of rule-breaking behavior on the association between total ADHD symptoms and disciplinary actions was significant for boys but not for girls. Further, when ADHD symptom dimensions were simultaneously included in the model, only hyperactive/impulsive symptoms were a positive predictor of rule-breaking behavior, and rule-breaking behavior mediated this link between hyperactive/impulsive symptoms and disciplinary actions. However, when examining ADHD symptom dimensions, no gender differences emerged. Implications for findings and future directions are discussed.

Why More Boys Than Girls With ADHD Receive Treatment: A Study of Dutch Twins

More boys than girls with attention deficit hyperactivity disorder (ADHD) receive treatment. One explanation for this bias may be that boys score higher on disruptive behavior scales than girls. Although this was supported by findings in clinical samples, recent studies in nonreferred samples showed that boys and girls with ADHD are similar with respect to their levels of disruptive behavior as reported by their mother. In this report, we investigate whether the difference in treatment rate is associated with higher teacher problem scores in boys with ADHD than in girls with ADHD. Data were obtained from mothers and teachers in a nonreferred sample of 283 boys and 291 girls with and without ADHD. Children were selected when they scored either low (controls) or high (probands) on attention problems. Mothers completed DSM-IV interviews, Child Behavior Checklists (CBCL) and the Conners Rating Scale (CRS). Teachers filled in the Teacher Report Form (TRF), and the CRS. Boys and girls with ADHD had similar levels of psychiatric illness and school impairment (such as being held back, special class placement and learning problems) by mother report. Mothers reported similar levels of aggression and attention problems in boys and girls with ADHD. In contrast, teachers consistently rated boys with ADHD as having higher scores on reports of attention problems and aggression than girls with ADHD. Gender differences vary across settings: boys and girls with ADHD are rated as behaving differently at school, but not at home. The higher level of teacher reported problem behavior at school may explain the high male–female ratio for ADHD in clinical settings. These findings have implications for the results of genetic studies that rely on referred samples, as these studies may give a distorted view of sex differences in the population.

Prevalence of prescribed attention-deficit hyperactivity disorder medications and diagnosis among Canadian preschoolers and school-age children: 1994-2007

OBJECTIVE

To describe trends in the prevalence of prescribed attention-deficit hyperactivity disorder (ADHD) medication by Canadian preschoolers and school-age children and to compare these with trends in the prevalence of the ADHD diagnosis between 1994 and 2007.

METHODS

Subjects participated in the National Longitudinal Survey on Children and Youth, a Canadian prospective survey collecting data biennially. Three cross-sectional samples of nonreferred children, aged 3 to 9 years and representative of Canadian children for 1994-1995 (n = 12 595), 2000-2001 (n = 13 904), and 2006-2007 (n = 14 655), were selected for the analyses. Information on prescribed medications and ADHD diagnosis was reported by each child's parents. Prevalence was estimated at each cycle, taking the child's age and sex into account.

RESULTS

The estimated prevalence of prescribed medications and ADHD diagnosis in Canada was generally low (less than 3%), but higher for boys (less than 4%) and school-age children (less than 5%). Preschoolers' prevalence of both prescribed medications and ADHD diagnosis stayed stable between 1994 and 2007 (1% or less), while that of school-age children increased nearly 2-fold. Boys' prevalence was higher than that of girls, but girls show the steepest increase over time, up to 2.1-fold. The association between prescribed medications and ADHD diagnosis has strengthened during the 2000s: a greater number of medications were used for children with ADHD (from 43% in 2000 to 59% in 2007) while off-label use of prescribed medications decreased among school-age children.

CONCLUSIONS

The upward trend in the prevalence of prescribed ADHD medications and ADHD diagnosis currently observed in contemporary societies is also occurring in Canada, except with preschoolers.

Sex differences in the manifestation of ADHD in emerging adults

OBJECTIVE

Given the mixed literature in the area, the aim of the current study was to determine whether sex differences exist in inattention, hyperactivity, and impairment in college adults with ADHD.

METHOD

Individuals from three universities were recruited for the study. Participants with (n = 164) and without ADHD (n = 710) completed on-line measures of symptoms and impairment.

RESULTS

College women with ADHD were shown to have higher rates of inattention, hyperactivity, and impairment than college women without ADHD and college men with ADHD. Analyses revealed that women in college who have ADHD experience higher levels of impairment in the following domains: home life, social life, education, money management, and daily life activities.

CONCLUSION

Overall, clear differences emerged between men and women with ADHD. Implications and future directions are discussed.

ADHD: clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder of childhood and can profoundly affect the academic achievement, well-being, and social interactions of children; the American Academy of Pediatrics first published clinical recommendations for the diagnosis and evaluation of ADHD in children in 2000; recommendations for treatment followed in 2001.