The scientific foundation for understanding attention-deficit/hyperactivity disorder as a valid psychiatric disorder

Perspectives on ADHD in children and adolescents as a social construct amidst rising prevalence of diagnosis and medication use

The diagnosis of attention-deficit hyperactivity disorder (ADHD) is based on the presence of pervasive, persistent symptoms of inattention and/or hyperactivity/impulsivity typically emerging early in life and resulting in significant functional impairment. In contrast to a worldwide epidemiological prevalence of approximately 5% in children and 2-3% in adults, there are significant variations in the prevalence of administrative ADHD diagnoses and medication use. We assert that in order to explore the underlying dynamics of this phenomenon, a thorough understanding of the construct ADHD is necessary. We contend that ADHD is not a natural entity that unfolds within an individual and can be understood independent from societal and environmental factors, but rather that ADHD as a diagnosis can better be conceptualized as a valid and pragmatically useful social construct. Decisions to diagnose and treat ADHD should follow a person-centered approach and be focused on functional impairment within a socially constructed, context-dependent and environmentally contingent model.

History of Childhood/Adolescence Referral to Speciality Care or Treatment in Adult Patients with Attention-Deficit/Hyperactivity Disorder: Mutual Relations with Clinical Presentation, Psychiatric Comorbidity and Emotional Dysregulation

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition that only rarely remits in adulthood. While several studies underlined differences between child and adult ADHD, the relationship between adult clinical presentation and early referral/treatment has been rarely investigated. In our study, 100 adults with ADHD were recruited and subdivided according to a history of referral to speciality care or treatment with methylphenidate (MPH) during childhood/adolescence. The early referral was associated with a history of disruptive behaviors during childhood/adolescence. Current ADHD symptoms were more pronounced in patients first referred during childhood/adolescence but never treated with MPH. Early MPH treatment was associated with lower rates of mood disorders and lower severity of emotional dysregulation at the time of assessment. Negative emotionality mediated the relationship between MPH treatment and mood disorders comorbidity. ADHD patients first referred during childhood/adolescence are characterized by more externalizing features than those first referred in adulthood. MPH treatment during the developmental age may have a role in preventing mood disorders in patients with ADHD, possibly by reducing emotional dysregulation.

Machine Learning and MRI-based Diagnostic Models for ADHD: Are We There Yet?

OBJECTIVE

Machine learning (ML) has been applied to develop magnetic resonance imaging (MRI)-based diagnostic classifiers for attention-deficit/hyperactivity disorder (ADHD). This systematic review examines this literature to clarify its clinical significance and to assess the implications of the various analytic methods applied.

METHODS

A comprehensive literature search on MRI-based diagnostic classifiers for ADHD was performed and data regarding the utilized models and samples were gathered.

RESULTS

We found that, although most studies reported the classification accuracies, they varied in choice of MRI modalities, ML models, cross-validation and testing methods, and sample sizes. We found that the accuracies of cross-validation methods inflated the performance estimation compared with those of a held-out test, compromising the model generalizability. Test accuracies have increased with publication year but were not associated with training sample sizes. Improved test accuracy over time was likely due to the use of better ML methods along with strategies to deal with data imbalances.

CONCLUSION

Ultimately, large multi-modal imaging datasets, and potentially the combination with other types of data, like cognitive data and/or genetics, will be essential to achieve the goal of developing clinically useful imaging classification tools for ADHD in the future.

Training a machine learning classifier to identify ADHD based on real-world clinical data from medical records

The diagnostic process of attention deficit hyperactivity disorder (ADHD) is complex and relies on criteria sensitive to subjective biases. This may cause significant delays in appropriate treatment initiation. An automated analysis relying on subjective and objective measures might not only simplify the diagnostic process and reduce the time to diagnosis, but also improve reproducibility. While recent machine learning studies have succeeded at distinguishing ADHD from healthy controls, the clinical process requires differentiating among other or multiple psychiatric conditions. We trained a linear support vector machine (SVM) classifier to detect participants with ADHD in a population showing a broad spectrum of psychiatric conditions using anonymized data from clinical records (N = 299 participants). We differentiated children and adolescents with ADHD from those not having the condition with an accuracy of 66.1%. SVM using single features showed slight differences between features and overlapping standard deviations of the achieved accuracies. An automated feature selection achieved the best performance using a combination 19 features. Real-world clinical data from medical records can be used to automatically identify individuals with ADHD among help-seeking individuals using machine learning. The relevant diagnostic information can be reduced using an automated feature selection without loss of performance. A broad combination of symptoms across different domains, rather than specific domains, seems to indicate an ADHD diagnosis.

Sparse representations of high dimensional neural data

Conventional Vector Autoregressive (VAR) modelling methods applied to high dimensional neural time series data result in noisy solutions that are dense or have a large number of spurious coefficients. This reduces the speed and accuracy of auxiliary computations downstream and inflates the time required to compute functional connectivity networks by a factor that is at least inversely proportional to the true network density. As these noisy solutions have distorted coefficients, thresholding them as per some criterion, statistical or otherwise, does not alleviate the problem. Thus obtaining a sparse representation of such data is important since it provides an efficient representation of the data and facilitates its further analysis. We propose a fast Sparse Vector Autoregressive Greedy Search (SVARGS) method that works well for high dimensional data, even when the number of time points is relatively low, by incorporating only statistically significant coefficients. In numerical experiments, our methods show high accuracy in recovering the true sparse model. The relative absence of spurious coefficients permits accurate, stable and fast evaluation of derived quantities such as power spectrum, coherence and Granger causality. Consequently, sparse functional connectivity networks can be computed, in a reasonable time, from data comprising tens of thousands of channels/voxels. This enables a much higher resolution analysis of functional connectivity patterns and community structures in such large networks than is possible using existing time series methods. We apply our method to EEG data where computed network measures and community structures are used to distinguish emotional states as well as to ADHD fMRI data where it is used to distinguish children with ADHD from typically developing children.

Cognitive Control Deficits in Children With Subthreshold Attention-Deficit/Hyperactivity Disorder

Subthreshold Attention-Deficit/Hyperactivity Disorder (ADHD) is defined as a neurobiological condition with some core inattentive or hyperactive/impulsive symptoms of ADHD which do not meet the full diagnosis clinically. Although it has been well documented that deficits in cognitive control, a high-level cognitive construct closely related to attention, are frequently found among children with ADHD, whether subthreshold ADHD is also associated with similar deficits remains unclear. In this study, we examined the attention functions and the cognitive control capacity (CCC) in children with ADHD (n = 39), those with subthreshold ADHD (n = 34), and typically developing peers (TD, n = 36). The results showed that the ADHD and subthreshold ADHD groups exhibited similar patterns of the impaired executive function of attention (revealed as an augment in flanker conflict effect) and reduced cognitive control capacity, and no significant difference was found between the two groups. These findings suggest that although children with subthreshold ADHD have not met the full criteria of ADHD, they showed reduced efficiency in cognitive control and attention function, similar to children with ADHD.

The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder

BACKGROUND

Misconceptions about ADHD stigmatize affected people, reduce credibility of providers, and prevent/delay treatment. To challenge misconceptions, we curated findings with strong evidence base.

METHODS

We reviewed studies with more than 2000 participants or meta-analyses from five or more studies or 2000 or more participants. We excluded meta-analyses that did not assess publication bias, except for meta-analyses of prevalence. For network meta-analyses we required comparison adjusted funnel plots. We excluded treatment studies with waiting-list or treatment as usual controls. From this literature, we extracted evidence-based assertions about the disorder.

RESULTS

We generated 208 empirically supported statements about ADHD. The status of the included statements as empirically supported is approved by 80 authors from 27 countries and 6 continents. The contents of the manuscript are endorsed by 366 people who have read this document and agree with its contents.

CONCLUSIONS

Many findings in ADHD are supported by meta-analysis. These allow for firm statements about the nature, course, outcome causes, and treatments for disorders that are useful for reducing misconceptions and stigma.

Age and Gender Measurement Noninvariance of the Adult ADHD Self-Report Scale Screener

Objective: The nature and form of demographics-related differences in ADHD self-reported symptoms across adulthood is currently poorly understood. This study explored the psychometrics of the Adult ADHD Self-Report Scale Screener (ASRS-6), including its age- and gender-related measurement invariance. Method: Structural equation models were used to analyze adult data-aged 16 to 95 years-from the 2007 British Adult Psychiatric Morbidity Survey. Results: The three-factor model (disorganization, inattention, hyperactivity) outperformed one- and two-factor models. Self-reported attentional deficits may be more pathognomonic of overall self-reported ADHD in adults than other symptoms. All items exhibited age measurement noninvariance while only a subset exhibited gender measurement noninvariance. Individuals who are male and younger tend to have lower thresholds for endorsement for ASRS-6 items than individuals who are female and older. Conclusion: The ASRS-6 does not appear to be unidimensional, and self-reported ASRS-6 symptomatology changes in meaning with age.

Neighborhood Socioeconomic Characteristics and Utilization of ADHD Medication in Schoolchildren: A Population Multilevel Study in Stockholm County

Objective: To examine the effects of neighborhood socioeconomic disadvantage and ethnic composition on the utilization of ADHD medication in schoolchildren after accounting for individual- and family-level characteristics. Method: A cohort of all schoolchildren living in Stockholm County was prospectively followed for new prescriptions of ADHD medication (N = 276,955). Three-level logistic regression models were used with individual/family characteristics (e.g., immigrant background) at the first level and small area market statistics (SAMS) and municipality characteristics (i.e., socioeconomic disadvantage and ethnic composition) at the second and third level. Results: SAMS socioeconomic disadvantage was associated with increased utilization of ADHD medication. The utilization of ADHD medication was lower among immigrant children as compared with natives, and their odds of not utilizing medication increased as the degree of concentration of foreign-born increased. Conclusion: These results suggest that interventions at the neighborhood level may offer an additional route for the prevention of the disorder and/or alleviation of its consequences.

Clinical Validation of Eye Vergence as an Objective Marker for Diagnosis of ADHD in Children

OBJECTIVE

ADHD youth show poor oculomotor control. Recent research shows that attention-related eye vergence is weak in ADHD children.

METHOD

To validate vergence as a marker to classify ADHD, we assessed the modulation in the angle of vergence of children ( n = 43) previously diagnosed with ADHD while performing an attention task and compared the results with age-matched clinical controls ( n = 19) and healthy peers ( n = 30).

RESULTS

We observed strong vergence responses in healthy participants and weak vergence in the clinical controls. ADHD children showed no significant vergence responses. Machine-learning models classified ADHD patients ( n = 21) from healthy controls ( n = 21) with an accuracy of 96.3% (false positive [FP]: 5.12%; false negative [FN]: 0%; area under the curve [AUC]: 0.99) and ADHD children ( n = 11) from clinical controls ( n = 14) with an accuracy of 85.7% (FP: 4.5%; FN: 19.2%, AUC: 0.90).

CONCLUSION

In combination with an attention task, vergence responses can be used as an objective marker to detect ADHD in children.

Attention-deficit hyperactivity disorder in ancient Greece: The Obtuse Man of Theophrastus

We present an ancient Greek description written by the philosopher Theophrastus in his classic book ' Characters' comparable with modern attention-deficit hyperactivity disorder. The arguments are based in one chapter of this book-The Obtuse Man-presenting features of a character closely resembling the modern description of attention-deficit hyperactivity disorder. In a free comparative exercise, we compared Theophrastus descriptions with modern Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) attention-deficit hyperactivity disorder symptoms. The sentences describing The Obtuse Man written by Theophrastus are similar to several symptoms of attention-deficit hyperactivity disorder and he would probably be currently diagnosed with this disorder as an adult. To our knowledge, this is the oldest description compatible with the current conception of attention-deficit hyperactivity disorder in adults in the Western literature. Differently than the moralistic view of ancient Greece regarding those symptoms, the medical attention-deficit hyperactivity disorder conception may be advantageous to patients since it might reduce prejudice and allow individuals to seek treatment.

Associations among ADHD, Abnormal Eating and Overweight in a non-clinical sample of Asian children

Attention-deficit/hyperactivity disorder (ADHD) has been found to be comorbid with obesity in adults, but the association in children is uncertain. Because the underlying mechanism of comorbidity in children has not been researched sufficiently, this study aims to explore the associations among ADHD, abnormal eating, and body mass index (BMI), as well as the mediating effect of depression in children. We conducted a cross-sectional study of 785 primary students in China. The parent-report version of ADHD Rating Scale-IV (ADHDRS-IV), the Child Eating Behaviour Questionnaire (CEBQ) and the Children’s Eating Attitude Test (ChEAT) were used to identify ADHD symptoms and abnormal eating. The Child Behavior Checklist (CBCL) was applied to assess depression. Structural Equation Modeling was carried out to clarify the associations between ADHD symptoms, depression, abnormal eating, and overweight of students. We found that ADHD positively contributed to emotional eating and Bulimia Nervosa symptoms. However, neither emotional eating nor Bulimia Nervosa symptoms was related to BMI in children. We also found that ADHD significantly contributed to depression, and depression directly predicted emotional eating. In conclusion, ADHD increased the risk of abnormal eating in children, while no significant relationship existed between ADHD and BMI. Comorbid depression raised the risk of emotional eating, rather than Bulimia Nervosa symptoms.

The Groundskeeper Gaming Platform as a Diagnostic Tool for Attention-Deficit/Hyperactivity Disorder: Sensitivity, Specificity, and Relation to Other Measures

OBJECTIVE

The purpose of this study was to assess the relative accuracies of the Conners' Brief Rating Scale, Parent Version, the Conners' Continuous Performance Test II (CPT II), and a novel interactive game called "Groundskeeper" to discriminate child psychiatric patients with and without attention-deficit/hyperactivity disorder (ADHD).

METHODS

We administered the three assessments to 113 clinically referred ADHD and non-ADHD patients who had been diagnosed with the Kiddie-Schedule of Affective Disorders and Schizophrenia- Present and Lifetime (K-SADS-PL), Version 19.

RESULTS

As measured by the area under the curve (AUC) statistic from receiver operating characteristic (ROC) analysis, the diagnostic accuracy of Groundskeeper (0.79) was as high as the accuracy of the Conners' parent rating of inattention (0.76) and better than the CPT II percent correct (0.62). Combining the three tests produced an AUC of 0.87. Correlations among the three measures were small and, mostly, not significant.

CONCLUSIONS

Our finding of similar diagnostic accuracies between Groundskeeper and the Conners' inattention scale is especially remarkable given that the Conners' inattention scale shares method variance with the diagnostic process. Although our work is preliminary, it suggests that computer games may be useful in the diagnostic process. This provides an important direction for research, given the objectivity of such measures and the fact that computer games are well tolerated by youth.

ADHD symptomatology is best conceptualized as a spectrum: a dimensional versus unitary approach to diagnosis

The aim of this paper is to build a case for the utility of conceptualizing ADHD, not as a unitary disorder that contains several subtypes, but rather as a marker of impairment in attention and/or impulsivity that can be used to identify one of several disorders belonging to a spectrum. The literature will be reviewed to provide an overview of what is known about ADHD in terms of heterogeneity in symptomatology, neuropsychology, neurobiology, as well as comorbidity with other diseases and treatment options. The data from these areas of research will be critically analyzed to support the construct of a spectrum of disorders that can capture the great variability that exists between individuals with ADHD and can discriminate between separate disorders that manifest similar symptoms. The symptoms associated with ADHD can be viewed as dimensional markers that point to a spectrum of related disorders that have as part of their characteristics impairments of attention and impulsivity. The spectrum can accommodate symmetrically and asymmetrically comorbid psychiatric disorders associated with ADHD as well as the wide heterogeneity known to be a part of the ADHD disorder. Individuals presenting with impairments associated with ADHD should be treated as having a positive marker for a spectrum disorder that has as part of its characteristics impairments of attention and/or impulsivity. The identification of impairment in attention and/or impulsivity should be a starting point for further testing rather than being an endpoint of diagnosis that results in pharmacological treatment that may or may not be the optimal therapy. Rather than continuing to attribute a large amount of heterogeneity in symptom presentation as well as a high degree of symmetric and asymmetric comorbidity to a single disorder, clinical evaluation should turn to the diagnosis of the type of attentional deficit and/or impulsivity an individual has in order to colocate the individual's disorder on a spectrum that captures the heterogeneity in symptomatology, the symmetrical and asymmetrical comorbidity, as well as subthreshold presentation and other variants often worked into the disorder of ADHD. The spectrum model can accommodate not only the psychophysiological profiles of patients, but is also consistent with what is known about the functional heterogeneity of the prefrontal cortex as well as the construct that cognitive processes are supported by overlapping and collaborative networks.

South African foundation phase teachers' perceptions of ADHD at private and public schools

This study investigated foundation phase teachers’ perceptions of Attention Deficit Hyperactivity Disorder (ADHD). The teachers’ views on the aetiology, appropriate interventions and incidence rates of ADHD were examined. A total of 130 foundation phase teachers from mainstream private and public schools completed a self-developed questionnaire that had been piloted by the researchers. Both descriptive and inferential statistics were used to analyse the data, specifically to determine whether there were differences in responses between public and private school teachers. Thematic content analysis was used to identify the themes that emerged from the open-ended questions. It was found that the teachers had a limited understanding of ADHD, in terms of what it is as well as the aetiology. In addition, it emerged that medication was the preferred method of intervention despite the participants’ awareness of alternative intervention methods. A comparison of the private and public school teachers’ results indicated no significant difference in their perceptions regarding the aetiology, interventions or incidence rates of ADHD.

Delinquency and association with behavioral disorders and substance abuse

Objective: to determine the incidence and associations of attention deficit-hyperactivity disorder (ADHD), conduct disorder (CD), and substance abuse disorder (SAD) in adolescents in conflict with the law in a Brazilian cohort. Methods: the Brazilian version of the Schedule for Affective Disorders and Schizophrenia for School Aged-Children (K-SADS-PL) was administered to 69 adolescent boys who were incarcerated for 45 days in the city of Curitiba, Brazil. Results: mean age was 15.5 years (range, 12-16.9 years) and most adolescents originated from disadvantaged social classes (87%). They resided in neighborhoods on the outskirts of the city or towns in the greater metropolitan area. Truancy and low educational achievement were common, with 73.9% not currently attending school and 43.4% not having finished the 5th grade. The great majority lived in single-parent families and many had relatives who themselves had problems with the law. Psychiatric disorders were apparent in 81.1% of the subjects, with the most common disorders being CD (59.4%), SAD (53.6%), and ADHD (43.5%). Both ADHD (p <0.001) and CD (p <0.01) had significant associations with substance abuse. Conclusion: in male adolescents in conflict with the law, ADHD, CD, and SAD were all found to be associated with delinquency.

Subthreshold attention-deficit/hyperactivity disorder is associated with functional impairments across domains: a comprehensive analysis in a large-scale community study

This study compared children who experience attention-deficit/hyperactivity disorder (ADHD) symptoms but do not meet criteria (i.e., subthreshold ADHD) with those with the full syndrome and healthy controls. Presence of ADHD symptoms was determined in a nationwide community sample of 921 children, aged 8-11 years. The main outcome measures comprised attentional symptoms, comorbidity profiles, academic performance, and neurocognitive ability (i.e., ADHD Rating Scale, Child Behavior Checklist, Learning Disability Evaluation Scale, and Stroop Color-Word Test, respectively). Subthreshold ADHD was equally prevalent in boys and girls, and more prevalent in low-income families. Throughout all the outcome measurements, subthreshold ADHD was both a significantly milder condition than full syndrome ADHD and a significantly more severe condition than non-ADHD status. The findings were consistent across the total as well as the subtest scores, and after correction for multiple comparisons (p < 0.0017). Children with subthreshold ADHD were found to experience significant symptoms and functional impairments. The results of this study support the clinical relevance of subthreshold ADHD in a childhood population. Subthreshold diagnostic criteria for ADHD may be more sensitive in detecting ADHD symptoms in girls than the full syndrome criteria, and subthreshold clinical, cognitive, and behavioral symptoms of ADHD may occur in a subset of children who are possibly more sensitive to their environment. Further consideration about the diagnostic threshold for ADHD may particularly benefit girls and children in low-income families.

Sons and daughters beyond your control: episodes in the prehistory of the attention deficit/hyperactivity syndrome

Hyperactive and inattentive children have been discussed in both the pedagogic and medical literature since the nineteenth century, and many controversies associated with attention deficit and hyperactivity disorder (ADHD) have been repeatedly analyzed in different contexts. The 'prehistory' of the ADHD concept-that is, up to the definition of ADHD in DSM-III and of the corresponding 'hyperkinetic disorder' in ICD-9-is outlined, with an emphasis on the literature not previously discussed in English language reviews of the subject.

A national epidemiological study of offending and its relationship with ADHD symptoms and associated risk factors

OBJECTIVE

The objective was to disentangle the relationship between offending, ADHD, and comorbid risk factors.

METHOD

A total of 11,388 students in further education completed a questionnaire, which measured nonviolent and violent delinquency, current ADHD symptoms, conduct disorder, substance use, association with delinquent peers, emotional lability, anger problems, violent attitudes, and low self-esteem.

RESULTS

The nonviolent and violent delinquency measures correlated significantly with all the predictor measures, with small to large effect sizes. Multiple regressions showed that after controlling for age and gender, ADHD contributed 8.2% and 8.8% to the variance in nonviolent and violent delinquency, respectively, but these effects were largely mediated by the comorbid measures, particularly substance use, association with delinquent peers, and conduct disorder.

CONCLUSION

The relationship between ADHD symptoms and offending among young people is largely explained indirectly by comorbid factors. A key prevention is to address substance use problems and association with delinquent peers.

Impaired response inhibition is associated with self-reported symptoms of depression, anxiety, and ADHD in female FMR1 premutation carriers

Fragile X Mental Retardation 1 (FMR1) premutation carriers (PM-carriers) have a defective trinucleotide expansion on the FMR1 gene that is associated with continuum of neuropsychological and mental disorders. Currently, little is known about the distinct subcomponents of executive function potentially impaired in female PM-carriers, and there have been no investigations into associations between executive function and incidences of mental disorders. A total of 35 female PM-carriers confirmed by Asuragen triple primed PCR DNA testing and 35 age- and intelligence-matched controls completed tests of executive function (i.e., response inhibition and working memory) and self-reported on social anxiety, depression, and ADHD predominantly inattentive (ADHD-PI) symptoms. Compared to controls, PM-carriers were significantly elevated on self-reported social anxiety and ADHD-PI symptoms. Irrespective of mental symptoms, female PM-carries performed significantly worse than controls on a response inhibition test, and further investigations revealed significant correlations between executive function performance and self-reported symptoms of anxiety, depression and ADHD-PI. Critically, among PM-carriers with good executive function performance, no women exceeded threshold markers for probable caseness of mental disorder. However, rates of probable caseness were elevated in those with average performance (response inhibition: social anxiety: 41.7%; depression: 20%; ADHD: 44.4%; working memory: social anxiety: 27.3%; depression: 9.1%; ADHD: 18.2%) and highly elevated for those with poor executive function performance (response inhibition: social anxiety: 58.3%; depression: 80%; ADHD: 55.6%; working memory: social anxiety: 100%; depression: 50%; ADHD: 83.3%). These data suggest that subtle executive dysfunction may be a useful neuropsychological indicator for a range of mental disorders previously reported in female PM-carriers.

The relationship between ADHD symptoms, mood instability, and self-reported offending

OBJECTIVE

To investigate the relative importance of ADHD symptoms, mood instability, and antisocial personality disorder traits in predicting self-reported offending.

METHOD

A total of 295 Icelandic students completed two scales of offending behavior and measures of ADHD symptoms, mood instability, and antisocial personality traits.

RESULTS

Self-reported offending from the two independent scales correlated significantly with ADHD symptoms, mood instability, and antisocial personality traits with medium to large effect size. Multiple regressions showed that ADHD symptoms contributed to the two outcome measures beyond that of age and gender with a medium effect size. The ADHD effects were only partly mediated by mood instability and antisocial personality traits for general offending but were almost completely mediated by the more reactive measure of antisocial behavior.

CONCLUSION

ADHD appears to be a potential risk factor for general offending in its own right irrespective of the presence of comorbidity, whereas mood instability is more important with regard to reactive behavior.

Biomarkers for attention-deficit/hyperactivity disorder (ADHD). A consensus report of the WFSBP task force on biological markers and the World Federation of ADHD

OBJECTIVE

Psychiatric "nosology" is largely based on clinical phenomenology using convention-based diagnostic systems not necessarily reflecting neurobiological pathomechanisms. While progress has been made regarding its molecular biology and neuropathology, the phenotypic characterization of ADHD has not improved. Thus, validated biomarkers, more directly linked to the underlying pathology, could constitute an objective measure for the condition.

METHOD

The task force on biological markers of the World Federation of Societies of Biological Psychiatry (WFSBP) and the World Federation of ADHD commissioned this paper to develop a consensus report on potential biomarkers of ADHD. The criteria for biomarker-candidate evaluation were: (1) sensitivity >80%, (2) specificity >80%, (3) the candidate is reliable, reproducible, inexpensive, non-invasive, easy to use, and (4) confirmed by at least two independent studies in peer-reviewed journals conducted by qualified investigators.

RESULTS

No reliable ADHD biomarker has been described to date, but some promising candidates (e.g., olfactory sensitivity, substantial echogenicity) exist. A problem in the development of ADHD markers is sample heterogeneity due to aetiological and phenotypic complexity and age-dependent co-morbidities.

CONCLUSIONS

Most likely, no single ADHD biomarker can be identified. However, the use of a combination of markers may help to reduce heterogeneity and to identify homogeneous subtypes of ADHD.

Personality disorders and clinical syndromes in ADHD prisoners

OBJECTIVE

The main objective of this article is to investigate the type of personality disorders and clinical syndromes (CSs) that were best related to ADHD symptoms among prisoners.

METHOD

The authors screened for childhood and adult ADHD symptoms and administered the Millon Clinical Multiaxial Inventory-III (MCMI-III) to 196 serving prisoners.

RESULTS

Childhood and adult ADHD symptoms were most strongly related to the compulsive (negative relationship) and borderline (positive relationship) scales on the MCMI-III with large and medium effect sizes, respectively. Hierarchical multiple regressions revealed that the absence of compulsive personality disorder traits (i.e., a low score as a dimension) was the single best Axis II predictor of childhood and adult ADHD symptoms. CSs did not add significantly to the variance in childhood ADHD beyond that of the personality disorder dimensions, but it did so for current ADHD symptoms in relation to alcohol dependence.

CONCLUSION

The findings demonstrate the relative absence of compulsive personality disorder traits in prisoners with ADHD symptoms as core maladaptive traits involving disorganization.

Callous-unemotional traits as a cross-disorders construct

PURPOSE

Callous-unemotional (CU) traits are currently viewed as the defining signs and symptoms of juvenile psychopathy. It is unclear, however, whether CU traits have validity only in the context of conduct disorder (CD) as proposed by Frick and Moffitt (A proposal to the DSM-V childhood disorders and the ADHD and disruptive behavior disorders work groups to include a specifier to the diagnosis of conduct disorder based on the presence of callous-unemotional traits, American Psychiatric Association, Washington, DC, 2010), or also outside CD, either in combination with other forms of psychopathology or as a stand-alone construct.

METHODS

The current review systematically studied the existent literature on CU traits in juveniles to examine their validity inside and outside CD according to the framework regarding the validity of a psychiatric diagnosis provided by Robins and Guze (Am J Psychiatry 126:983-987, 1970).

RESULTS

Inside youth with conduct problems, and CD specifically, it seems that CU traits meet the Robins and Guze criteria. As many of the reviewed studies included youth with ODD and ADHD as well, there are indications the same might be true for ODD and ADHD, although probably to a lesser extent. In other disorders, CU traits may be present as well, but their role is not firmly established. As stand-alone construct, data are lacking or are scarce on all of the above-mentioned criteria.

CONCLUSIONS

CU traits are a useful specifier in CD, and possibly also in disruptive behaviour disorders (DBDs) more generally. High CU traits outside DBDs exist but it is as yet unknown if there is a clinical need for defining CU traits as a stand-alone construct.

Lifespan attention deficit/hyperactivity disorder and borderline personality disorder symptoms in female patients: a latent class approach

Attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) are frequently comorbid. To contribute to a better understanding of the associations regularly found between ADHD and BPD, on the one hand, and the developmental pathways for these disorders, on the other hand, latent class analyses (LCA) were undertaken to identify classes differing in profiles of childhood symptoms of ADHD and adult symptoms of ADHD and BPD. Diagnostic interviews with 103 female outpatients meeting the criteria for ADHD and/or BPD were used to assess current DSM-IV symptoms; childhood symptoms of ADHD were assessed in parent interviews. The latent classes were examined in relation to the DSM-IV conceptualizations of ADHD and BPD. And relations between childhood and adult classes were examined to hypothesize about developmental trajectories. LCA revealed an optimal solution with four distinct symptom profiles: only ADHD symptoms; BPD symptoms and only ADHD symptoms of hyperactivity; BPD symptoms and ADHD symptoms of inattention and hyperactivity; BPD symptoms and ADHD symptoms of inattention, hyperactivity and impulsivity. All patients with BPD had some ADHD symptoms in both adulthood and childhood. Hyperactivity was least discriminative of adult classes. Adult hyperactivity was not always preceded by childhood hyperactivity; some cases of comorbid ADHD and BPD symptoms were not preceded by significant childhood ADHD symptoms; and some cases of predominantly BPD symptoms could be traced back to combined symptoms of ADHD in childhood. The results underline the importance of taking ADHD diagnoses into account with BPD. ADHD classification subtypes may not be permanent over time, and different developmental pathways to adult ADHD and BPD should therefore be investigated.

Disparities in ADHD assessment, diagnosis, and treatment

The regional study by Baumgardner and colleagues converges with existing literature to clearly show that the distribution of ADHD diagnosis falls along socioeconomic lines, according to the relative wealth of neighborhoods. This adds additional evidence that trends in the diagnosis and treatment for ADHD in children move in the exact opposite direction from those who are at highest risk for meeting criteria, for experiencing impairment, for and downstream socioeconomic sequelae. Contributing factors, such as marginal diagnoses (such as when parent and teacher symptom reports diverge), inadequate insurance coverage, limited time, and lack of familiarity and comfort with diagnostic and prescribing guidelines, may leave the door open to misdiagnosis and treatment. In some cases, this may take the form of over-diagnosis and over-treatment, in the form of false-positive diagnoses with ADHD, and treatments for it, or may alternatively take the form of false-negative diagnoses. If the social and epidemiological data are any indication, it is furthermore likely that such false-positive or false-negative outcomes may break along socioeconomic lines. Increased use of formal screening tools, increased curricular time for mental health in primary care residencies, support for physicians in the field in the form of referral options and remote consultation and support, may all serve to improve quality of care for individual patients, and may also serve to regularize treatment across socioeconomic and sociodemographic lines, hence reducing disparities. Further research is needed to study the root causes and dynamics that create such disparities, but the steps outlined above may help in the near term.

The history of attention deficit hyperactivity disorder

The contemporary concept of attention deficit hyperactivity disorder (ADHD) as defined in the DSM-IV-TR (American Psychiatric Association 2000) is relatively new. Excessive hyperactive, inattentive, and impulsive children have been described in the literature since the nineteenth century. Some of the early depictions and etiological theories of hyperactivity were similar to current descriptions of ADHD. Detailed studies of the behavior of hyperactive children and increasing knowledge of brain function have changed the concepts of the fundamental behavioral and neuropathological deficits underlying the disorder. This article presents an overview of the conceptual history of modern-day ADHD.

Attention-deficit/hyperactivity disorder: associations with overeating and obesity

In the past decade, we have become increasingly aware of strong associations between overweight/obesity and symptoms of attention-deficit/hyperactivity disorder (ADHD) in children, adolescents, and adults. This review addresses the prevalence of the comorbidity and discusses some of the mechanisms that could account for their relationship. It is suggested that the inattentive and impulsive behaviors that characterize ADHD could contribute to overeating in our current food environment, with its emphasis on fast food consumption and its many food temptations. It is also proposed-based on the compelling evidence that foods high in fat, sugar, and salt are as addictive as some drugs of abuse-that excessive food consumption could be a form of self-medication. This view conforms with the well-established evidence that drug use and abuse are substantially higher among those with ADHD than among the general population.

Twenty-four-week treatment with extended release methylphenidate improves emotional symptoms in adult ADHD

OBJECTIVES

Treatment investigations with methylphenidate in adults with ADHD focus preferentially on the classical psychopathology: inattention, hyperactivity and impulsivity. ADHD-associated emotional symptoms, which are frequently present at least in ADHD subpopulations, were studied rarely. The vast majority of the placebo-controlled trials had observation periods between 4 and 8 weeks. To assess the medium- to long-term effects of extended release methylphenidate (MPH-ER) on emotional symptoms and other psychopathology frequently seen in ADHD patients, we conducted a large-scale, multicenter treatment study.

METHODS

We performed a randomised, 24-week, double-blind, placebo-controlled study in adults with ADHD. The diagnosis was made on the basis of the DSM-IV criteria, which were confirmed by clinical history and a structured psychopathological interview and the use of rating instruments. 363 patients were randomized to MPH-ER or placebo at a ratio of 2:1. The duration of the titration period was 5 weeks followed by a maintainance phase of 19 weeks. The efficacy measures were the observer rated 10-item Emotional Dysregulation Scale (EDS) derived from the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS) and a self-report, six-item Emotional Lability Scale (ELS) extracted from the long version of the Conners Adult ADHD Self Report Scale (CAARS:S:L). In addition we used the SCL-90-R for the assessment of ADHD associated and comorbid psychopathology.

RESULTS

MPH-ER was statistically superior to placebo in reducing emotional symptoms as assessed by the EDS and the ELS. Obsessive-compulsive symptoms and those of problems with self-concept declined until the end of the observation period. The decline was more pronounced in MPH-ER treated individuals. The effects remained robust during the entire maintenance period until week 24. Symptoms of anxiety, depression, anger and hostility, phobia, paranoid ideations and psychoticism were not improved.

CONCLUSIONS

MPH-ER appears to be an efficacious treatment for emotional symptoms with ADHD. Also obsessive-compulsive symptoms and problems with self-concept were affected positively.

Sex differences in the functional neuroanatomy of working memory in adults with ADHD

OBJECTIVE

Although attention deficit hyperactivity disorder (ADHD) in adults is associated with significant morbidity and dysfunction and afflicts both sexes, relatively few imaging studies have examined female subjects and none have had sufficient power to adequately examine sex differences. The authors examined sex differences in the neural functioning of adults with ADHD during performance of a verbal working memory task.

METHOD

The participants were 44 adults with ADHD matched on age, sex, and estimated IQ to 49 comparison subjects. Accuracy and reaction time on an N-back task were measured to assess working memory. The blood-oxygen-level-dependent functional MRI response was used as a measure of neural activity.

RESULTS

A group-by-sex analysis of variance showed no between-group differences in either reaction time or percent correct for the working memory task. For both sexes combined, the adults with ADHD showed less activity than comparison subjects in prefrontal regions. However, sex-by-group analyses revealed an interaction, such that male ADHD subjects showed significantly less activity in right frontal, temporal, and subcortical regions and left occipital and cerebellar regions relative to male comparison subjects, whereas female ADHD subjects showed no differences from female comparison subjects. Exploratory correlation analyses revealed negative associations between working-memory-related activation and number of hyperactive symptoms for men and number of inattentive symptoms for women.

CONCLUSIONS

Male but not female adults with ADHD showed significantly altered patterns of neural activity during a verbal working memory task. Men and women showed different associations between neural activity and ADHD symptoms.

Unveiling the mystery about adult ADHD: one woman's journey

Attention deficit hyperactivity disorder (ADHD), a neurobiological disorder, affects millions of individuals and can significantly impact an individual's life course. Research guidelines used in assessment, diagnosis, and treatment have focused primarily on Caucasian males generating, in part, the need to redress how gender and other contextual factors are considered. Consequently many women and persons from diverse cultural groups can be ignored or misdiagnosed. Undiagnosed and untreated women with ADHD are therefore limited in their potential to flourish socially, academically, interpersonally, and in their family roles. This case example of a 38-year-old African American woman illustrates how her life journey was affected by undiagnosed ADHD.

The relationship between satisfaction with life, ADHD symptoms, and associated problems among university students

OBJECTIVE

To ascertain whether ADHD symptoms, and associated problems, are negatively related to subjective well-being.

METHOD

The Satisfaction With Life Scale (SWLS) was completed by 369 university students, along with the Reasoning & Rehabilitation (R&R) ADHD Training Evaluation (RATE), the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) Scale for current ADHD symptoms, and the Depression Anxiety Stress Scales (DASS).

RESULTS

The SWLS was negatively correlated with all the other measures, and the strongest correlations were with the Total RATE score. A multiple regression analysis showed that the variables in the study accounted for 22% and 25% of the variance of the SWLS among males and females, respectively. Among males poor social functioning was the best predictor of dissatisfaction with life, whereas among females it was poor emotional control.

CONCLUSION

Both ADHD symptoms and associated problems are significantly related to poorer satisfaction with life.

Towards conceptualizing a neural systems-based anatomy of attention-deficit/hyperactivity disorder

Convergent data from neuroimaging, neuropsychological, genetic and neurochemical studies in attention-deficit/hyperactivity disorder (ADHD) have implicated dysfunction of the dorsolateral prefrontal cortex (DLPFC) and dorsal anterior cingulate cortex (dACC), which form the cortical arm of the frontostriatal network supporting executive functions. Furthermore, besides the DLPFC and dACC, structural and functional imaging studies have shown abnormalities in key brain regions within distributed cortical networks supporting attention. The conceptualization of neural systems biology in ADHD aims at the understanding of what organizing principles have been altered during development within the brain of a person with ADHD.Characterizing these neural systems using neuroimaging could be critical for the description of structural endophenotypes, and may provide the capability of in vivo categorization and correlation with behavior and genes.

Beyond polemics: science and ethics of ADHD

What is attention-deficit hyperactivity disorder (ADHD)? Why are so many children being diagnosed with ADHD and prescribed medication? Are stimulant drugs an effective and safe treatment strategy? This article explores the current state of scientific research into ADHD and the key social and ethical concerns that are emerging from the sharp rise in the number of diagnoses and the use of stimulant drug treatments in children. Collaborations among scientists, social scientists and ethicists are likely to be the most promising route to understanding what ADHD is and what stimulant drugs do.

Self-regulation and internal resources in school-aged children with ADHD symptomatology: an investigation using the Rorschach inkblot method

This study assesses the capacity for emotional self-regulation and internal resources in a sample of urban children with ADHD symptomatology using the Rorschach Inkblot Method (RIM). Because these children have profound difficulty with modulating their affect, it is hypothesized that this difficulty would be reflected on RIM variables that have traditionally been thought to reflect the internal resources necessary for these children to regulate emotions. Children with greater ADHD symptoms were found to display lower scores on variables indicating internal resources for emotional self-regulation and stress tolerance (M, EA) relative to a comparison group with fewer ADHD symptoms. The research and clinical implications of these findings are discussed.

Children, ADHD, and citizenship

The diagnosis of attention-deficit hyperactivity disorder is a subject of controversy, for a host of reasons. This paper seeks to explore the manner in which children's interests may be subsumed to those of parents, teachers, and society as a whole in the course of diagnosis, treatment, and labeling, utilizing a framework for children's citizenship proposed by Elizabeth Cohen. Additionally, the paper explores aspects of discipline associated with the diagnosis, as well as distributional pathologies resulting from the application of the diagnosis in potentially biased ways.

Linkage analysis of attention deficit hyperactivity disorder

Results of behavioral genetic and molecular genetic studies have converged to suggest that both genes contribute to the development of ADHD. Although prior linkage studies have produced intriguing results, their results have been inconsistent, with no clear pattern of results emerging across studies. We genotyped 5,980 SNPs across the genome in 1,187 individuals from families with children diagnosed with ADHD. We then performed two nonparametric linkage analyses on ADHD families: (1) an affected sibling pair linkage analysis on 217 families with 601 siblings diagnosed with ADHD and (2) a variance components linkage analysis using the number of ADHD symptoms as the phenotype on 260 families with 1,100 phenotyped siblings. The affection status linkage analysis had a maximum LOD score of 1.85 on chromosome 8 at 54.2 cM. The maximum LOD score in the variance components linkage analysis was 0.8 on chromosome 8 at 93.4 cM. The absence of regions of significant or suggestive linkage in these data suggest that there are no genes of large effect contributing to the ADHD phenotype.

Genome-wide association scan of attention deficit hyperactivity disorder

Results of behavioral genetic and molecular genetic studies have converged to suggest that genes substantially contribute to the development of attention deficit/hyperactivity disorder (ADHD), a common disorder with an onset in childhood. Yet, despite numerous linkage and candidate gene studies, strongly consistent and replicable association has eluded detection. To search for ADHD susceptibility genes, we genotyped approximately 600,000 SNPs in 958 ADHD affected family trios. After cleaning the data, we analyzed 438,784 SNPs in 2,803 individuals comprising 909 complete trios using ADHD diagnosis as phenotype. We present the initial TDT findings as well as considerations for cleaning family-based TDT data. None of the SNP association tests achieved genome-wide significance, indicating that larger samples may be required to identify risk loci for ADHD. We additionally identify a systemic bias in family-based association, and suggest that variable missing genotype rates may be the source of this bias.

Fatty acid status and behavioural symptoms of attention deficit hyperactivity disorder in adolescents: a case-control study

BACKGROUND

Most studies of Attention-deficit hyperactivity disorder (ADHD) have focused on either young children or older adults. The current study compared 11 ADHD adolescents with 12 age-matched controls. The purpose was to examine differences in dietary intake, particularly of essential fatty acids, and determine whether this could explain the typical abnormalities in red blood cell fatty acids observed in previous studies of young children. A secondary purpose was to determine if there were relationships between circulating concentrations of essential fatty acids and specific ADHD behaviours as measured by the Conners' Parent Rating Scale (CPRS-L).

METHODS

Eleven ADHD adolescents and twelve age-matched controls were recruited through newspaper ads, posters and a university website. ADHD diagnosis was confirmed by medical practitioners according to DSM-IV criteria. Blood, dietary intake information as well as behavioural assessments were completed.

RESULTS

Results showed that ADHD adolescents consumed more energy and fat than controls but had similar anthropometry. ADHD children consumed equivalent amounts of omega-3 and omega-6 fatty acids to controls, however they had significantly lower levels of docosahexaenoic acid (DHA, 22:6n-3) and total omega-3 fatty acids, higher omega-6 fatty acids and a lower ratio of n-3:n-6 fatty acids than control subjects. In addition, low omega-3 status correlated with higher scores on several Conners' behavioural scales.

CONCLUSION

These data suggest that adolescents with ADHD continue to display abnormal essential fatty acid profiles that are often observed in younger children and distinctly different from normal controls of similar age. Further these red blood cell fatty acid differences are not explained by differences in intake. This suggests that there are metabolic differences in fatty acid handling between ADHD adolescents and normal controls. The value of omega-3 supplements to improve fatty acid profiles and possibly behaviours associated with ADHD, need to be examined.

Does dopaminergic reward system contribute to explaining comorbidity obesity and ADHD?

Some recent studies have reported a strong link between obesity and attention-deficit/hyperactivity disorder (ADHD). However, to date, the factors underlying this newly described comorbidity are still unclear and unexplored. In the present article, we proposed that the dopamine system and implicate dopamine genes contribute to explaining the association between ADHD and obesity. The background for this hypothesis comes from studies on the association between ADHD and dopamine, as well as from investigations on dopamine in obese individuals. There is strong evidence that indicate catecholamines dopamine is very important in the pathophysiology of ADHD, as well as in the mechanism of therapeutic action of stimulant drugs. Furthermore, increasing evidence indicated that dopaminergic reward system is significantly associated with obesity. With regard to the therapeutic implications, recent studies indicate that methylphenidate (MPH) - a drug widely used for ADHD reduced overall energy intake with a selective reduction in dietary fat. Findings are consistent with a reward deficiency model of obesity whereby low brain dopamine predicts overeating and obesity, and administering agents that increase dopamine results in reduced feeding behavior. Given the above background, we hypothesize that the increased prevalence of ADHD in obese individual could be explained by the imbalance of dopaminergic reward system.

Predictors of diagnostic delay in a clinical sample of French children with attention-deficit/hyperactivity disorder

BACKGROUND

Early recognition of attention-deficit/hyperactivity disorder (ADHD) may improve the educational and psychosocial outcome of most affected children. To date, factors associated with diagnostic delay of ADHD have not specifically been addressed. Aims of this study were to evaluate the mean diagnostic delay (time between first consultation and definite diagnosis) in a clinical sample of French children with ADHD referred to an outpatient university clinic, and to determine associated factors.

METHOD

A total of 129 consecutively referred ADHD patients aged 6-16 years. A detailed history of the children was obtained from their parents. The Kiddie-SADS-PL, the ADHD-Rating Scale, and the Clinical Global Impression Scale were used for clinical assessment.

RESULTS

Mean diagnostic delay was 32.89 months. A previous suspicion of ADHD by any health care professional, therapist or teacher was significantly associated with a reduced diagnostic delay. Co-morbidity with anxiety/depressive disorders and previous contact with a mental health professional were associated with a significant delay in diagnosis.

CONCLUSION

Delay in diagnosis of ADHD in France is among the longest reported. Children with co-morbid anxiety or depressive disorders are particularly at risk of having a significant delay in the diagnosis. Health professionals, therapists and teachers may play a relevant role to accelerate the diagnostic procedure.