Late-Onset ADHD: Understanding the Evidence and Building Theoretical Frameworks

Sleep Physiology and Neurocognition Among Adolescents With Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Few studies have characterized the nature of sleep problems among adolescents with attention-deficit/hyperactivity disorder (ADHD) using polysomnography (PSG). Additionally, although adolescents with ADHD and adolescents with sleep disturbances display similar neurocognitive deficits, the role of sleep in contributing to neurocognitive impairment in adolescent ADHD is unknown. This study investigated differences in PSG-measured sleep among adolescents with ADHD compared with non-psychiatric controls and associations with neurocognition.

METHOD

Medication-free adolescents aged 13 to 17 (N = 62, n = 31 with ADHD; mean age = 15.3 years; 50% female) completed a diagnostic evaluation, 3 nights of ambulatory PSG, the Cambridge Neuropsychological Test Automated Battery, and subjective reports of sleep and executive functioning. Linear regressions covarying for age, sex, and pubertal status examined group differences in sleep indices, and partial Pearson correlations assessed relations between sleep and neurocognition.

RESULTS

Although adolescents with ADHD did not exhibit differences in PSG-measured sleep duration, awakenings, or latency (ps > .05) compared with non-psychiatric controls, they displayed lower slow wave sleep percentage (β = -.40) and non-rapid eye movement (NREM) electroencephalogram (EEG) delta power (β = -.29). They also exhibited greater stage 2 percentage (β = .41), NREM EEG sigma power (β = .41), and elevated self-reported sleep disturbances (ps < .05). Lower NREM EEG delta power, increased high-frequency power, and slower decline in NREM EEG delta power overnight were associated with poorer neurocognition among adolescents with ADHD.

CONCLUSIONS

Adolescents with ADHD reported more sleep disturbances than non-psychiatric controls and exhibited differences in sleep stage distribution and NREM sleep EEG frequency. Sleep-EEG spectral indices were associated with impaired neurocognition, suggesting that physiological sleep processes may underlie neurocognitive deficits in ADHD. Future studies may clarify whether sleep plays a causal role in neurocognitive impairments in adolescent ADHD and whether interventions normalizing sleep improve neurocognition.

CLINICAL TRIAL REGISTRATION INFORMATION

Sleep Dysfunction and Neurocognitive Outcomes in Adolescent ADHD; https://clinicaltrials.gov/; NCT02897362.

DIVERSITY & INCLUSION STATEMENT

We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. We actively worked to promote sex and gender balance in our author group. While citing references scientifically relevant for this work, we also actively worked to promote sex and gender balance in our reference list.

Is prevention of ADHD and comorbid conditions in adolescents possible?

OBJECTIVES

To examine how the concept of prevention is applicable to adolescent ADHD, which preventive interventions may be feasible, and which methods can be used to evaluate effectiveness.

METHOD

Following a literature search for prevention clinical trials relevant to adolescent ADHD, selected studies are critically reviewed to identify suitable targets and promising interventions.

RESULTS

There is some evidence from controlled studies that interventions delivered to prepubertal children at high risk for ADHD or diagnosed with ADHD may decrease the incidence or persistence of ADHD in adolescence. Uncontrolled follow-up of clinical samples and population studies suggest that treatment of adolescents with ADHD can decrease the risk for several negative functional outcomes in youth. A controlled trial found a specific cognitive training intervention to decrease risky driving.

CONCLUSIONS

Prevention of ADHD and associated negative outcomes is possible and of high clinical relevance. Assessing prevention effects is methodologically challenging, but feasible.

The Ability of Self-Report Methods to Accurately Diagnose Attention Deficit Hyperactivity Disorder: A Systematic Review

OBJECTIVE

To identify and analyze all studies validating rating scales or interview-based screeners commonly used to evaluate ADHD in adults.

METHOD

A systematic literature search identified all studies providing diagnostic accuracy statistics, including sensitivity and specificity, supplemented by relevant articles or test manuals referenced in reviewed manuscripts.

RESULTS

Only 20 published studies or manuals provided data regarding sensitivity and specificity when tasked with differentiating those with and without ADHD. While all screening measures have excellent ability to correctly classify non-ADHD individuals (with negative predictive values exceeding 96%), false positive rates were high. At best, positive predictive values in clinical samples reached 61%, but most fell below 20%.

CONCLUSION

Clinicians cannot rely on scales alone to diagnose ADHD and must undertake more rigorous evaluation of clients who screen positive. Furthermore, relevant classification statistics must be included in publications to help clinicians make statistically defensible decisions. Otherwise, clinicians risk inappropriately diagnosing ADHD.

Annual Research Review: Perspectives on progress in ADHD science - from characterization to cause

The science of attention-deficit/hyperactivity disorder (ADHD) is motivated by a translational goal - the discovery and exploitation of knowledge about the nature of ADHD to the benefit of those individuals whose lives it affects. Over the past fifty years, scientific research has made enormous strides in characterizing the ADHD condition and in understanding its correlates and causes. However, the translation of these scientific insights into clinical benefits has been limited. In this review, we provide a selective and focused survey of the scientific field of ADHD, providing our personal perspectives on what constitutes the scientific consensus, important new leads to be highlighted, and the key outstanding questions to be addressed going forward. We cover two broad domains - clinical characterization and, risk factors, causal processes and neuro-biological pathways. Part one focuses on the developmental course of ADHD, co-occurring characteristics and conditions, and the functional impact of living with ADHD - including impairment, quality of life, and stigma. In part two, we explore genetic and environmental influences and putative mediating brain processes. In the final section, we reflect on the future of the ADHD construct in the light of cross-cutting scientific themes and recent conceptual reformulations that cast ADHD traits as part of a broader spectrum of neurodivergence.

Partizipation von Studierenden mit neurokognitiven Beeinträchtigungen am Beispiel von ADHS und spezifischen Lernstörungen

Zusammenfassung: Das Hauptziel des vorliegenden Beitrags ist eine kritische Reflexion der Situation von Studierenden mit neurokognitiven Beeinträchtigungen in Hinblick auf deren Partizipation im universitären Setting. Nach einer kurzen Erläuterung der aktuellen universitätsrechtlichen Rahmenbedingungen in Deutschland, Österreich und der Schweiz werden (i) am Beispiel von Aufmerksamkeitsstörungen und spezifischen Lernstörungen charakteristische Schwierigkeiten von betroffenen Studierenden beim Studium anhand von Fallvignetten dargestellt und (ii) Ziele in Hinblick auf eine gelingende Partizipation und Chancengleichheit für Studierende mit Beeinträchtigungen skizziert. Anhand eines tentativen Rahmenmodells zur Förderung der Partizipation diskutieren wir die Notwendigkeit differenzierter universitätsinterner und -externer struktureller Rahmenbedingungen, die zusätzlich zu den bereits bestehenden – aber nicht ausreichenden – universitätsinternen Maßnahmen wie dem Nachteilsausgleich implementiert werden sollten.

ADHD in Adults: A Systematic Review and Meta-Analysis of Prevalence Studies in Outpatient Psychiatric Clinics

OBJECTIVE

Systematic review and meta-analysis to estimate the pooled prevalence of ADHD in adult attendees of outpatient mental health clinics and to investigate factors influencing prevalence rates.

METHODS

The following were extracted: demographics, design of the study (screening only or two-phase), scales/criteria for diagnosis of ADHD, number of ADHD, and non-ADHD participants.

RESULTS

The pooled prevalence of ADHD from screening studies (n = 9) was 26.7%, (95% CI [17.2-37.4]), ADHD = 1727, No ADHD = 3,578. From studies employing a two-stage design (n = 5), prevalence was 14.61%, CI [10.39-19.41], ADHD = 561, No ADHD = 3,578. Age and gender did not have any significant effect on the estimated prevalence. By contrast exclusion of psychotic disorders lowers prevalence. The screening scale used also influence prevalence rates.

CONCLUSION

Meta-analysis shows high rates of adult ADHD among psychiatric outpatient clinics. Applying DSM-5 criteria increased prevalence rates. More methodologically robust studies, using two-stage design, need to be conducted to help assist in service planning.

Adult-Onset ADHD: A Critical Analysis and Alternative Explanations

Attention deficit/hyperactivity disorder (ADHD) is characterized as a neurodevelopmental disorder. However, data from several recent studies suggest that there may be adults who meet current criteria for ADHD, yet did not experience symptoms until adulthood (i.e., "adult-onset ADHD"). This systematic review evaluated and synthesized the empirical evidence on adult-onset ADHD to answer the question: Is the extant literature strong enough to evaluate adult-onset ADHD? Nine studies met strict inclusion/exclusion criteria. Results suggest that the methodologies of the extant studies were not strong enough to evaluate adult-onset ADHD. Insufficient methodologies provide presently unclear information about the nature of late-onset symptoms. These symptoms seem to exist but their source could be (1) adult-emergent symptoms that were previously surpassed due to lower environmental demands/supportive facilitators, (2) mimics that were not properly assessed, or (3) childhood-onset symptoms that were not detected earlier due to failure to come to clinical attention. Future directions, clinical recommendations, and limitations of the literature and the current review are discussed.

Regularity and Timing of Sleep Patterns and Behavioral Health Among Adolescents

OBJECTIVE

Sleep is vital to supporting adolescent behavioral health and functioning; however, sleep disturbances remain under-recognized and undertreated in many health care settings. One barrier is the complexity of sleep, which makes it difficult for providers to determine which aspects-beyond sleep duration-may be most important to assess and treat to support adolescent health. This study examined associations between 2 sleep indices (regularity and timing) and adolescent behavioral health and functioning over and above the impact of shortened/fragmented sleep.

METHOD

Eighty-nine adolescents recruited from the community (mean age = 14.04, 45% female participants) completed 7 days/nights of actigraphy and, along with a parent/guardian, reported on behavioral health (internalizing and externalizing symptoms) and psychosocial functioning. Stepwise linear regressions examined associations between sleep timing and regularity and behavioral/functional outcomes after accounting for shortened/fragmented sleep.

RESULTS

Delayed sleep timing was associated with greater self-reported internalizing (F[6,82] = 11.57, p = 0.001) and externalizing (F[6,82] = 11.12, p = 0.001) symptoms after accounting for shortened/fragmented sleep. Irregular sleep was associated with greater self-reported and parent-reported externalizing symptoms (self: F[7,81] = 6.55, p = 0.01; parent: F[7,80] = 6.20, p = 0.01) and lower psychosocial functioning (self: F[7,81] = 6.03, p = 0.02; parent: F[7,78] = 3.99, p < 0.05) after accounting for both shortened/fragmented sleep and delayed sleep timing.

CONCLUSION

Sleep regularity and timing may be critical for understanding the risk of poor behavioral health and functional deficits among adolescents and as prevention and intervention targets. Future work should focus on developing and evaluating convenient, low-cost, and effective methods for addressing delayed and/or irregular adolescent sleep patterns in real-world health care settings.

Do we over-diagnose ADHD in North America? A critical review and clinical recommendations

There has been a marked increase in the prevalence of attention-deficit/hyperactivity disorder (ADHD) in the last 25 years in North America. Some see this trend as positive and believe that it reflects a better identification of ADHD and even think that the disorder is still under-diagnosed. Others, however, contend that ADHD is over-diagnosed. To help mental health clinicians to maintain an informed and nuanced perspective on this debate, this critical review aims to (1) summarize empirical results on factors that might contribute to increase the number of ADHD diagnoses and (2) propose clinical recommendations coherent with these findings to improve clinical practices for ADHD assessment and treatment. We conclude that artifactual factors such as current formulation of diagnostic criteria, clinical practices, and inordinate focus on performance, which is rampant in North America, likely contribute to inflated prevalence rates.

ADHD in Children and Adults: Diagnosis and Prognosis

Attention-Deficit Hyperactivity Disorder (ADHD) is a prevalent neuropsychiatric disorder associated with significant impairment and distress throughout the lifespan. Recent investigations have shed light on different aspects regarding the trajectory of ADHD, including reports on risk factors in childhood, that are associated with remission or persistence in adulthood. Despite significant advances in our understanding of the pathophysiology of the disorder, the diagnosis of ADHD remains strictly clinical and is based on behavioral symptoms of inattention, impulsivity, and hyperactivity. In this chapter we review the diagnostic process of ADHD, discuss the clinical presentation of the disorder across the lifespan, and examine patterns of comorbidity and longitudinal predictor of outcomes.

Characterizing the heterogeneous course of inattention and hyperactivity-impulsivity from childhood to young adulthood

To advance understanding of the heterogeneity in the course of ADHD, joint symptom trajectories of inattention and hyperactivity-impulsivity from childhood to young adulthood were modelled and associated with genetic, demographic, and clinical characteristics. Data were obtained from the NeuroIMAGE cohort which includes 485 individuals with ADHD, their 665 siblings, and 399 typically developing children. Trajectories were based on scores of the Conners Parent Rating Scale Revised and estimated over seven homogeneous age bins (from 5 to 28 years) using parallel process latent class growth analysis on data collected across 2-4 time points. Multilevel multinomial logistic regression was used to identify characteristics that differentiated between the derived classes. A seven-class solution revealed "severe combined stable" (4.8%), "severe combined decreasing" (13%), "severe inattentive stable" (4.8%), "moderate combined increasing" (7.5%), "moderate combined decreasing" (12.7%), "stable mild" (12.9%), and "stable low" (44.3%) classes. Polygenic risk for depression, ADHD diagnosis, ADHD medication use, IQ, comorbid symptom levels (foremost oppositional behaviour), and functional impairment levels differentiated classes with similar ADHD symptom levels in childhood but a diverging course thereafter. The course of ADHD is highly heterogeneous, with stable, decreasing, and increasing trajectories. Overall, severe symptom levels in childhood are associated with elevated-to-severe symptom levels in adolescence and young adulthood, despite substantial symptom reductions. Beyond symptom severity in childhood, genetic, demographic, and clinical characteristics distinguish the heterogeneous course.

Attention-deficit/hyperactivity disorder has a state-dependent association with asthma: The role of systemic inflammation in a population-based birth cohort followed from childhood to adulthood

There is a high comorbidity between attention-deficit/hyperactivity disorder (ADHD) and asthma, and inflammation has been proposed as a potential pathophysiological mechanism behind this association. Most studies conducted so far have used a cross-sectional design, and none has evaluated the prevalence of asthma symptoms in patients with ADHD followed from childhood to adulthood. We relied on data from the 1993 Pelotas birth cohort to evaluate the association between ADHD and asthma in patients with distinct patterns of incidence, persistence and remission, and to explore the potential role of inflammatory markers in the comorbidity. We analyzed data from 3281 individuals from the 1993 Pelotas birth cohort collected at birth (1993), 11 years (2004), 18 years (2011), and 22 years (2015). Subjects were first classified according to their ADHD and asthma status as early-onset (EO) persistent (positive screening for ADHD at 11 years and diagnosis of ADHD according to DSM-5, except criterion E, at either 18 or 22 years), EO-remittent (positive screening for ADHD at 11 years only), late-onset (diagnosis of ADHD according to DSM-5, except criterion E, at 18 or 22 years only), or healthy subjects (negative for both conditions in all evaluation). After controlling for confounders, significant associations were observed between EO-remittent ADHD and EO-remittent asthma (OR 1.68, 95% CI 1.11-2.55), EO-persistent ADHD and EO-persistent asthma (OR 4.33, 95% CI 1.65-11.34), and between late-onset ADHD and late-onset asthma (OR 1.86, 95% CI 1.28-2.70), suggesting a state-dependent association. Serum interleukin-6 (IL-6) and C-reactive protein (CRP) were measured at the 18- and 22-year evaluations and compared between subjects positive for ADHD, asthma, and subjects with both or none conditions, regardless of the previously defined trajectories. Subjects with comorbid ADHD and asthma presented higher levels of IL-6 at the 18- and 22-year evaluations when compared to subjects negative for both conditions. Our results demonstrate a state-dependent association between ADHD and asthma despite underlying trajectories. Higher levels of serum IL-6 in patients with both conditions suggest that a pro-inflammatory environment might have a role in the pathophysiological mechanisms underlying the comorbidity.

A Systematic Review and Comparison of Neurocognitive Features of Late-Life Attention-Deficit/Hyperactivity Disorder and Dementia With Lewy Bodies

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) in adulthood and dementia with Lewy bodies (DLB) share many cognitive and noncognitive similarities. The overlapping features between both disorders complicate differential diagnosis. The aim of the current systematic review was to compare patterns of neuropsychological profiles in older adults with ADHD and DLB.

METHOD

Of the 1989 ADHD-related articles and 1332 DLB-related articles screened, 3 ADHD and 25 DLB articles were retained for qualitative synthesis and review.

RESULTS

A synthesis of individual study findings revealed isolated working memory deficits for late-life ADHD, and performance deficits in areas of attention, memory, language, and visuoperceptual abilities for DLB. Results were limited by small samples and absence of data in some cognitive domains.

CONCLUSION

These initial findings support potentially unique neurocognitive profiles for ADHD in later life and DLB that would enable practitioners to differentially diagnose and appropriately treat older adults presenting with these phenotypically similar disorders.

Detection of Feigned ADHD Using the MOXO-d-CPT

Objective: The objective of this study was to assess the MOXO-d-CPT utility in detecting feigned ADHD and establish cutoffs with adequate specificity and sensitivity. Method: The study had two phases. First, using a prospective design, healthy adults who simulated ADHD were compared with healthy controls and ADHD patients who performed the tasks to the best of their ability (n = 47 per group). Participants performed the MOXO-d-CPT and an established performance validity test (PVT). Second, the MOXO-d-CPT classification accuracy, employed in Phase 1, was retrospectively compared with archival data of 47 ADHD patients and age-matched healthy controls. Results: Simulators performed significantly worse on all MOXO-d-CPT indices than healthy controls and ADHD patients. Three MOXO-d-CPT indices (attention, hyperactivity, impulsivity) and a scale combining these indices showed adequate discriminative capacity. Conclusion: The MOXO-d-CPT showed promise for the detection of feigned ADHD and, pending replication, can be employed for this aim in clinical practice and ADHD research.

A Qualitative Analysis of Contextual Factors Relevant to Suspected Late-Onset ADHD

Objective: Recent studies suggest attention-deficit/hyperactivity disorder (ADHD) may emerge post-childhood. We integrate qualitative methods to systematically characterize contextual factors that may (a) delay identification of ADHD in childhood and (b) inform why ADHD symptoms emerge post-childhood. Method: Suspected late-onset ADHD cases from the local normative comparison group of the Multimodal Treatment Study of ADHD completed a qualitative interview (14 young adults and 7 caregivers). Interviews were qualitatively analyzed. Results: We identified five themes. Three themes may attenuate or delay identification of childhood ADHD: external factors (e.g., supportive adults), internal factors (e.g., strong intellectual functioning), and other factors (e.g., dismissive attitudes toward ADHD). Two themes may accompany an increase in ADHD symptoms post-childhood: external factors (e.g., increased external demands) and internal factors (e.g., perceived stress). Conclusion: Clinicians should probe these factors in suspected late-onset cases to address (a) whether, how, and to what extent ADHD was attenuated in childhood and (b) why symptoms emerge post-childhood.

Adolescent Attention-Deficit/Hyperactivity Disorder: Understanding Teenage Symptom Trajectories

Symptoms of attention-deficit/hyperactivity disorder (ADHD) run a variable course through adolescence. While most affected individuals show some improvement, particularly of hyperactivity-impulsivity, symptoms of inattention are more persistent, and some individuals may meet diagnostic criteria for the first time during adolescence. Genetic factors affect adolescent symptom trajectories; those showing persistence likely carry a greater burden of common risk alleles. Rare structural genomic variants, such as copy number variants and point mutations, might also play a role. Although psychostimulant medication is associated with better functional outcomes, an impact on underlying adolescent symptom trajectories has been hard to demonstrate. At a neural level, several studies report that adolescents whose childhood ADHD symptoms have remitted are indistinguishable from neurotypical individuals. This finding could reflect the "carrying forward" of relatively typical childhood neural features among those destined for adolescent remission or the correction of early childhood anomalies with a convergence toward typical dimensions. Other studies have noted unique, possibly compensatory patterns of neural activity among adolescents whose ADHD has improved. Finally, different neural processes might occur in different brain regions. Thus, some functional imaging studies find that subcortical anomalies reflect the onset of ADHD and remain throughout life regardless of symptom change, whereas the variable clinical course of adolescent ADHD is determined by plasticity of the cerebral cortex. Integrating an understanding of the neural processes with genomic risk could elucidate the mechanisms underlying the complex course of adolescent ADHD.

Financial decision-making in a community sample of adults with and without current symptoms of ADHD

Research found that adults with attention deficit hyperactivity disorder (ADHD) have more problems with financial decision-making than healthy controls. The present study investigates the impact of symptoms of ADHD on impulsive buying and the use of financial decision styles. Furthermore, the influence of personality, symptoms of depression and demographics on the association between ADHD and these aspects of financial decision-making is evaluated. A community sample of 1292 participants (age range 18–93 years, 45.4% male) completed questionnaires related to ADHD, impulsive buying, financial decision styles, personal financial situation, depression and personality. Four groups were formed based on self-reported ADHD symptoms: an ‘ADHD’ group (n = 45), an ‘Adult-only ADHD’ group (n = 57), a ‘Subthreshold ADHD’ group (n = 162) and a ‘No ADHD’ group (n = 265). Groups were compared using ANOVA and chi-square tests. Furthermore, multiple regression analyses in the complete sample were employed to examine the association between ADHD and financial decision-making. The ADHD and Adult-only ADHD groups reported significantly more impulsive buying, used more often an avoidant or spontaneous decision style and less often saved money compared to the No ADHD group. Regression analyses revealed that impulsive buying and financial decision styles were not significantly associated with ADHD symptoms when controlling for personality, symptoms of depression and demographics. The present study confirms previous research on adults with ADHD by indicating more impulsive buying and a more frequent use of disadvantageous financial decision styles (i.e., avoidant and spontaneous styles) in individuals with an elevated number of current symptoms of ADHD compared to individuals without symptoms of ADHD. Personality and demographic variables were found to be related to both impulsive buying and the use of specific financial decision styles and might be of influence on the association between impulsive buying, the use of financial decision styles and ADHD.

Disease burden and direct medical costs of incident adult ADHD: A retrospective longitudinal analysis based on German statutory health insurance claims data

Background.

Adult attention-deficit/hyperactivity disorder (aADHD) is still a largely unrecognized psychiatric condition despite its strong impact on individuals’ well-being. Here, we describe the healthcare situation of individuals with incident aADHD over 4 years before and 4 years after initial administrative diagnosis.

Methods.

A retrospective, longitudinal cohort analysis was conducted using German claims data. The InGef database contained approximately 5 million member-records from over 60 nationwide statutory health insurances (SHI). Individuals were indexed upon initial diagnosis of aADHD.

Results.

Average age at diagnosis of aADHD was 35 years, and 60% of individuals were male. Comorbidities, resource use, and healthcare costs were substantial before initial diagnosis and decreased within the 4 years thereafter. Only 32% of individuals received initial ADHD medication and adherence was low. The majority received psychotherapy. Individuals with initial ADHD medication showed the highest share in comorbidities, physician visits, medication use for comorbidities, psychotherapy, and costs. Overall, healthcare costs were at over €4,000 per individual within the year of aADHD diagnosis.

Conclusions.

We conclude that earlier recognition of aADHD could prevent the development and aggravation of comorbid mental illnesses. At the same time, comorbid conditions may have masked (“over-shadowed”) aADHD and delayed diagnosis. The burden of disease in aADHD is high, which was noticeable especially among individuals who received initial ADHD-medication, suggesting that psychopharmacological treatment was mainly considered for the most severely ill. We conclude that measures to facilitate access of aADHD patients to clinical experts are required to improve reality of care in the outpatient setting.

Reduced fronto-striatal volume in attention-deficit/hyperactivity disorder in two cohorts across the lifespan

Attention-Deficit/Hyperactivity Disorder (ADHD) has been associated with altered brain anatomy in neuroimaging studies. However, small and heterogeneous study samples, and the use of region-of-interest and tissue-specific analyses have limited the consistency and replicability of these effects. We used a data-driven multivariate approach to investigate neuroanatomical features associated with ADHD in two independent cohorts: the Dutch NeuroIMAGE cohort (n = 890, 17.2 years) and the Brazilian IMpACT cohort (n = 180, 44.2 years). Using independent component analysis of whole-brain morphometry images, 375 neuroanatomical components were assessed for association with ADHD. In both discovery (corrected-p = 0.0085) and replication (p = 0.032) cohorts, ADHD was associated with reduced volume in frontal lobes, striatum, and their interconnecting white-matter. Current results provide further evidence for the role of the fronto-striatal circuit in ADHD in children, and for the first time show its relevance to ADHD in adults. The fact that the cohorts are from different continents and comprise different age ranges highlights the robustness of the findings.

The 10-year trend in drug prescriptions for attention-deficit/hyperactivity disorder (ADHD) in Germany

Purpose

The aim of this study was to analyse whether the global trend in drug prescriptions for attention-deficit hyperactivity disorders (ADHD), as observed during the last years and often criticized as medicalization, have remained stable or shifted.

Methods

This observational study was based on a secondary analysis of data from a large German database including patients with an ADHD diagnosis between 2008 and 2018. Prescription data comprised all important ADHD drugs.

Results

A total of 620 practices delivered data from a total of 77,504 patients (31% of them females) with a diagnosis of AHDH. Nearly 38% (29,396/77,504) of all patients received, at least, one prescription for an ADHS medicine between 2008 and 2018. The number of patients receiving a drug steadily increased annually until 2012 and then slowly fell, but unevenly distributed across the age groups. While the number of younger patients ( ≤ 16 years) receiving a prescription fell by 24% and the defined daily doses (DDDs) remained stable, the number of patients between 17 and 24 years receiving a prescription increased by 113% and the DDDs by 150%. Respectively, the number of older adults (≥ 25 years) with a prescription increased by 355% and the DDDs by 515%. Nearly one-third of older adults received an ADHD medicine only once.

Conclusion

The ever-increasing prescription of ADHD medicines stopped some years ago for children. ADHS and its pharmacological management are increasingly observed among older adolescents and adults, with a different pattern of drug persistence compared with children.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02948-3) contains supplementary material, which is available to authorized users.

Differential implications of persistent, remitted, and late-onset ADHD symptoms for substance abuse in women and men: A twin study from ages 11 to 24

BACKGROUND

Persistence and emergence of ADHD in adulthood are associated with substance problems. We investigate differential implications of ADHD course for tobacco, alcohol, or marijuana problems by sex, then whether substance misuse results from ADHD or contributes to it, through a twin differences design.

METHODS

A population-based cohort of 998 twins (61 % monozygotic; 52 % female), born in Minnesota from 1988 to 1994, was prospectively assessed from ages 11-24. Childhood ADHD was oversampled. At age 24, 255 had a history of childhood-onset ADHD (160 persistent, 95 remitted); 93 had late-onset ADHD symptoms identified in late-adolescence/adulthood. Persistent, remitted, and late-onset groups were compared to those without ADHD (N = 459) on childhood characteristics and age-24 substance problems.

RESULTS

Persistent and late-onset groups differed in childhood; twin concordances suggested greater genetic etiology for persistent ADHD. As adolescents, however, both groups were high in conduct problems; by adulthood, they were comparably high in substance problems. In particular, women whose ADHD persisted were 5 times more likely to develop tobacco use disorder than women without ADHD. Remitted ADHD was associated with less-increased risk, except for alcohol problems among women. Consistent with possible causality, monozygotic female twins with more age-17 ADHD symptoms than co-twins had more age-24 tobacco symptoms; a similar association was found for alcohol.

CONCLUSIONS

Presence or emergence of ADHD in early adulthood increases substance problems to a greater degree for women than men. While effects of substances on later ADHD were not statistically significant, detection was limited by the relative rarity of late-adolescent substance symptoms.

Comorbidity and health services' usage in children with autism spectrum disorder: a nested case-control study

AIMS

Children with autism spectrum disorder (ASD) tend to suffer from various medical comorbidities. We studied the comorbidity burden and health services' utilisation of children with ASD to highlight potential aetiologies and to better understand the medical needs of these children.

METHODS

In this nested case-control study, ASD cases and controls - matched by age, sex and ethnicity in a 1:5 ratio - were sampled from all children born between 2009 and 2016 at a tertiary medical centre. Data were obtained from the hospital's electronic database. Comorbid diagnoses were classified according to pathophysiological aetiology and anatomical/systemic classification of disease. Standard univariate and multivariate statistics were used to demonstrate comorbidities and health services' utilisation patterns that are significantly associated with ASD.

RESULTS

ASD children had higher rates of comorbidities according to both pathophysiological and anatomical/systemic classifications (p < 0.001). The most marked significant differences were observed for: hearing impairments (OR = 4.728; 95% CI 2.207-10.127) and other auricular conditions (OR = 5.040; 95% CI 1.759-14.438); neurological (OR = 8.198; 95% CI 5.690-11.813) and ophthalmological (OR = 3.381; 95% CI 1.617-7.068) conditions; and ADD/ADHD (OR = 3.246; 95% CI 1.811-5.818). A subgroup analysis revealed a more profound case-control difference in anaemia rates among girls than in boys (OR = 3.25; 95% CI 1.04-10.19 v. OR = 0.74; 95% CI 0.33-1.64 respectively) and an opposite trend (larger differences in males than in females in cardiovascular diseases (OR = 1.99; 95% CI 1.23-3.23 v. OR = 0.76; 95% CI 0.17-3.45, respectively)). In addition, larger case-control differences were seen among Bedouin children than in Jewish children in a number of medical comorbidities (Breslow-Day test for homogeneity of odds ratio p-value <0.05). Finally, we found that children with ASD tended to be referred to the emergency department and to be admitted to the hospital more frequently than children without ASD, even after adjusting for their comorbidity burden (aOR = 1.28; 95% CI 1.08-1.50 and aOR = 1.28; 95% CI 1.11-1.47 for >1 referrals and admissions per year, respectively).

CONCLUSIONS

The findings of this study contribute to the overall understanding of comorbid conditions and health services' utilisation for children with ASD. The higher prevalences of comorbidities and healthcare services' utilisation for children with ASD highlight the additional medical burden associated with this condition.

Associations between sleep problems and ADHD symptoms among adolescents: findings from the Shandong Adolescent Behavior and Health Cohort (SABHC)

Study Objectives

Sleep problems and symptoms of attention-deficit hyperactivity disorder (ADHD) in adolescence are common. Little is known about the prospective the prospective associations between sleep and subsequent ADHD symptoms in adolescents. This study examined the prospective associations between sleep problems and subsequent ADHD symptoms in a large sample of adolescents.

Methods

Participants included 7072 adolescents from the Shandong Adolescent Behavior and Health Cohort (SABHC) study in Shandong, China. Participants were initially assessed in November–December of 2015 and were reassessed 1-year later in 2016. Sleep duration, sleep problems, and psychosocial information were collected using a structured questionnaire. ADHD symptoms were measured by the Achenbach Child Behavior Checklist-Youth Self-Report.

Results

At baseline, 7.6% participants had clinically relevant ADHD symptoms, which were highly comorbid with sleep problems including insomnia symptoms, poor sleep quality, symptoms of restless legs syndrome (RLS), frequent snoring, and short sleep duration. Of the 6531 participants without clinically relevant ADHD symptoms at baseline, 4.5% reported clinically relevant ADHD symptoms at 1-year follow-up. After adolescent and family covariates were adjusted for, insomnia (OR = 2.09, 95% CI = 1.45–3.02), RLS (OR = 1.47, 95% CI = 1.02–2.11), and frequent snoring (OR = 2.30, 95% CI = 1.36–3.90) were all significantly associated with subsequent ADHD symptoms.

Conclusion

ADHD symptoms and sleep problems are highly comorbid. Insomnia, RLS and frequent snoring appear to be significant predictors of subsequent ADHD symptoms. Our study highlights the importance of assessing and managing sleep problems for prevention and clinical treatment of ADHD symptoms in adolescence.

The Prevalence of "Late-Onset" ADHD in a Clinically Referred Adult Sample

OBJECTIVE

Three recent prospective longitudinal studies of population cohorts reported nontrivial rates of "adult-onset" ADHD. Given that this result is at odds with the neurodevelopmental conceptualization of ADHD, as well as with general clinical experience, we obtained report of onset of symptoms in a clinical sample of adults diagnosed with ADHD.

METHOD

One hundred four adults diagnosed with ADHD completed retrospective ratings of DSM-IV/DSM-5 ADHD symptoms between the ages of 5 and 12 years.

RESULTS

Fifty percent of the sample met full retrospective child diagnostic symptom criteria of six ADHD symptoms in either the inattentive or hyperactive-impulsive domains. Seventy-five percent met a less stringent criterion of four symptoms in either domain.

DISCUSSION

These results are interpreted in light of a dimensional model of ADHD that posits emergence of ADHD symptoms and corresponding impairment as a function of increasing performance demands and/or decreasing environmental supports during the course of development.

A risk calculator to predict adult attention-deficit/hyperactivity disorder: generation and external validation in three birth cohorts and one clinical sample

AIM

Few personalised medicine investigations have been conducted for mental health. We aimed to generate and validate a risk tool that predicts adult attention-deficit/hyperactivity disorder (ADHD).

METHODS

Using logistic regression models, we generated a risk tool in a representative population cohort (ALSPAC - UK, 5113 participants, followed from birth to age 17) using childhood clinical and sociodemographic data with internal validation. Predictors included sex, socioeconomic status, single-parent family, ADHD symptoms, comorbid disruptive disorders, childhood maltreatment, ADHD symptoms, depressive symptoms, mother's depression and intelligence quotient. The outcome was defined as a categorical diagnosis of ADHD in young adulthood without requiring age at onset criteria. We also tested Machine Learning approaches for developing the risk models: Random Forest, Stochastic Gradient Boosting and Artificial Neural Network. The risk tool was externally validated in the E-Risk cohort (UK, 2040 participants, birth to age 18), the 1993 Pelotas Birth Cohort (Brazil, 3911 participants, birth to age 18) and the MTA clinical sample (USA, 476 children with ADHD and 241 controls followed for 16 years from a minimum of 8 and a maximum of 26 years old).

RESULTS

The overall prevalence of adult ADHD ranged from 8.1 to 12% in the population-based samples, and was 28.6% in the clinical sample. The internal performance of the model in the generating sample was good, with an area under the curve (AUC) for predicting adult ADHD of 0.82 (95% confidence interval (CI) 0.79-0.83). Calibration plots showed good agreement between predicted and observed event frequencies from 0 to 60% probability. In the UK birth cohort test sample, the AUC was 0.75 (95% CI 0.71-0.78). In the Brazilian birth cohort test sample, the AUC was significantly lower -0.57 (95% CI 0.54-0.60). In the clinical trial test sample, the AUC was 0.76 (95% CI 0.73-0.80). The risk model did not predict adult anxiety or major depressive disorder. Machine Learning approaches did not outperform logistic regression models. An open-source and free risk calculator was generated for clinical use and is available online at https://ufrgs.br/prodah/adhd-calculator/.

CONCLUSIONS

The risk tool based on childhood characteristics specifically predicts adult ADHD in European and North-American population-based and clinical samples with comparable discrimination to commonly used clinical tools in internal medicine and higher than most previous attempts for mental and neurological disorders. However, its use in middle-income settings requires caution.

Annual Research Review: Does late-onset attention-deficit/hyperactivity disorder exist?

Attention-deficit/hyperactivity disorder (ADHD) is conceptualized as an early onset childhood neurodevelopmental disorder. Prevalence in adults is around two-thirds that in childhood, yet longitudinal outcome studies of children with ADHD found a minority continue to meet full criteria in adulthood. This suggests that not all adult cases meet ADHD criteria as children, a conclusion supported by earlier studies relying on retrospective recall in adolescent and adult samples. More recently prospective follow-up of population and control samples suggest that adolescent and young adult ADHD is not always a continuation of childhood ADHD. Here, we review the literature on age of onset, to explore whether late-onset ADHD exists, and if so, examine the evidence for whether this should be considered the same or a different disorder as childhood onset ADHD. We conclude that current evidence supports the view that a significant proportion of young adults meeting criteria for ADHD would not have met full diagnostic criteria for ADHD as children. However, many in the late-onset group show some ADHD symptoms in childhood, or an externalizing disorder such as oppositional defiant disorder. Furthermore, the current studies suggest that most (but not all) cases of late-onset ADHD develop the disorder between the ages of 12-16 and can therefore be considered adolescent or early adult onset ADHD. There is a relative lack of data spanning young to older adulthood to address the question of adult-onset. Currently, there is insufficient data to clarify the extent to which early and late onset ADHD reflect a different balance of genetic and environmental risks or share the same underlying neural mechanisms. Clinicians should be aware that significantly impairing forms of ADHD can emerge beyond the age of 12 years, although perhaps rarely in the context of a complete absence of precursors. The current evidence on treatment responses is limited.

Commentary: ADHD lifetime trajectories and the relevance of the developmental perspective to Psychiatry: reflections on Asherson and Agnew-Blais, (2019)

Asherson and Agnew-Blais review evidence from prospective, longitudinal studies in Brazil, New Zealand, Sweden, the United Kingdom and the United States showing that ADHD can emerge for the first time in adolescence or young adulthood. These findings defy conventional wisdom specifying that ADHD is, by definition, a disorder that emerges in childhood. We discuss possible explanations for the late-onset of ADHD, including the removal in adolescence or young adulthood of features of a young person's environment that played a buffering role against the emergence of symptoms and heterotypic continuity in a general liability to psychopathology that is present from childhood.

Treatment strategies for ADHD: an evidence-based guide to select optimal treatment

Attention-deficit/hyperactivity disorder (ADHD) is a common and impairing disorder affecting children, adolescents, and adults. Several treatment strategies are available that can successfully ameliorate symptoms, ranging from pharmacological to dietary interventions. Due to the increasing range of available options, an informed selection or prioritization of treatments is becoming harder for clinicians. This review aims to provide an evidence-based appraisal of the literature on ADHD treatment, supplemented by expert opinion on plausibility. We outline proposed mechanisms of action of established pharmacologic and non-pharmacologic treatments, and we review targets of novel treatments. The most relevant evidence supporting efficacy and safety of each treatment strategy is discussed. We review the individualized features of the patient that should guide the selection of treatments in a shared decision-making continuum. We provide guidance for optimizing initiation of treatment and follow-up of patients in clinical settings.

Editorial Perspective: Delayed circadian rhythm phase: a cause of late-onset attention-deficit/hyperactivity disorder among adolescents?

Late-onset attention-deficit/hyperactivity disorder (ADHD) has been a topic of significant debate within our field. One question focuses on whether there may be alternative explanations for the onset of inattentive and/or hyperactive symptoms in adolescence. Adolescence is a developmental period associated with a normative circadian rhythm phase delay, and there is significant overlap in the behavioral and cognitive manifestations and genetic underpinnings of ADHD and circadian misalignment. Delayed circadian rhythm phase is also common among individuals with traditionally diagnosed ADHD, and exposure to bright light may be protective against ADHD, a process potentially mediated by improved circadian timing. In addition, daytime sleepiness is prevalent in late-onset ADHD. Despite these converging lines of evidence, circadian misalignment is yet to be considered in the context of late-onset ADHD - a glaring gap. It is imperative for future research in late-onset ADHD to consider a possible causal role of delayed circadian rhythm phase in adolescence. Clarification of this issue has significant implications for research, clinical care, and public health.

Investigating late-onset ADHD: a population cohort investigation

BACKGROUND

Adult ADHD has been assumed to be a continuation of childhood-onset ADHD. However, recent studies have identified individuals with ADHD in adulthood who have not had ADHD in childhood. Whether or not these individuals have a 'typical' neurodevelopmental profile is not clear.

METHODS

We tested two explanations for the emergence of apparent late-onset ADHD symptomatology using the ALSPAC epidemiological cohort, by grouping individuals according to their scores on the Strengths and Difficulties Questionnaire (SDQ) hyperactivity subscale at ages 12 and 17 years. First, we tested whether some of those with apparent late-onset ADHD symptoms had been potentially misclassified on the basis of earlier SDQ hyperactivity scores (ages 7, 8 and 9 years) or of subthreshold symptoms at age 12 years. Second, we investigated the possibility that those with 'genuine' late-onset ADHD symptoms had a delayed manifestation of the same liability that underlies childhood-onset symptoms, by investigating whether they had a similar profile of neurodevelopmental impairments (in the domains of autistic symptomatology, language, reading, spelling, executive functioning and IQ) as those with typical childhood-onset ADHD.

RESULTS

N = 56/75 (75%) of those with apparent late-onset ADHD had had high ADHD scores at least one point in childhood, suggesting that they may have been misclassified on the basis of their score at age 12 years. The remaining 19 individuals (25%) with genuine late-onset ADHD symptoms did not show a profile of neurodevelopmental impairment typically seen in ADHD, instead showing similar levels of autistic symptoms, language skills, executive functioning ability and IQ to those without ADHD symptoms. The only exceptions were that this group showed reading and spelling problems at age 9 years.

CONCLUSIONS

Our work suggests that this small number of individuals with genuine late-onset symptoms may not be most appropriately considered as having a typical neurodevelopmental disorder.

Growing out of attention deficit hyperactivity disorder: Insights from the 'remitted' brain

We consider developmental and cognitive models to explain why some children 'grow out' of attention deficit hyperactivity disorder (ADHD) by adulthood. The first model views remission as a convergence towards more typical brain function and structure. In support, some studies find that adult remitters are indistinguishable from those who were never affected in the neural substrates of 'top-down' mechanisms of cognitive control, some 'bottom-up' processes of vigilance/response preparation, prefrontal cortical morphology and intrinsic functional connectivity. A second model postulates that remission is driven by the recruitment of new brain systems that compensate for ADHD symptoms. It draws support from demonstrations of atypical, but possibly beneficial, patterns of connectivity within the cognitive control network in adult remitters. The final model holds that some childhood ADHD anomalies show lifelong persistence, regardless of adult outcome, supported by shared reports of anomalies in remitters and persisters in posterior cerebral and striato-thalamic regions. The models are compatible: different processes driving remission might occur in different brain regions. These models provide a framework for future studies which might inform novel treatments to 'accelerate' remission.