Dr Søren Dalsgaard

Hot Topic Symposium

Sex differences in ADHD

In one of the opening sessions of the meeting, Dr Steve Lee (UCLA Department of Psychology, Los Angeles, CA, USA) described a meta-analysis (18 studies) of psychiatric comorbidities in girls with ADHD compared with those without.1 He noted that girls with ADHD were more likely to be diagnosed with anxiety, depression, oppositional defiant disorder (ODD) and conduct disorder (CD) compared with those without ADHD, highlighting that there is persuasive evidence for comorbidity in girls.

Dr Ronna Fried (Clinical and Research Programs in Pediatric Psychopharmacology, Harvard Medical School, Boston, MA, USA) went on to present results from two studies conducted at Massachusetts General Hospital (MGH) in boys and girls with and without ADHD which estimated the lifetime burden of comorbid psychiatric disorders at 5- and 10-year follow-up. She highlighted that the ratio of boys:girls with comorbid ODD reduced over the 10-year period but increased in those with comorbid CD. In those patients with comorbid bipolar disorder (BD), rates were similar at baseline and at 5 years, but at 10 years, boys were more likely to have comorbid BD than girls. She also noted that at 10 year follow-up, there was a large increase in bulimia in girls with ADHD compared with those without.

In the presentation by Dr Takuya Saito (Hokkaido University Graduate School of Medicine, Department of Child and Adolescent Psychiatry, Sapporo, Japan), he noted that until recently adult ADHD was not even recognised in Japan and that, although patients with ADHD are at high risk of comorbidity, there are currently no published studies which have examined adult ADHD and psychiatric comorbidity in Japanese populations. Dr Saito went on to compare results from his unpublished study in Japan, which when compared with results from other countries (Germany, South Korea, Sweden, US), highlighted the differences in rates of comorbid depression and BD observed among cultures and that there is a need for a standardised international collaborative study.

In the final presentation of this hot topic symposium, Dr Søren Dalsgaard (National Centre for Register-Based Research, NCRR, Aarhus University, Denmark) presented results from the adult ADHD outcomes studies using the Danish Register. In summary, he noted in a follow-up study of 208 patients with ADHD until a mean age of 31 years, that 22.6% had an inpatient psychiatric admission in adulthood and that girls with conduct disorders in childhood had a higher risk than boys (HR: 2.4; 95% CI 1.1–5.6).2 He also explained that females were at higher risk for substance use disorders (alcohol, cannabis, other illicit drugs) compared with males.3 When discussing all-cause mortality in ADHD, Dr Dalsgaard presented results showing that patients with ADHD were 2.07x more likely to die compared with those without ADHD (fully adjusted mortality rate), and that there were no significant differences between the genders (p=0.091).4 However, he did emphasise that age of ADHD diagnosis had an effect on mortality rates with adults with ADHD having a 4.25x likelihood of dying compared with adult controls.4

Dr Dalsgaard: “Why do females with ADHD have poorer outcomes? … Are referred females more ‘severe’ than referred males? … Are males more likely to be misdiagnosed with ADHD? … Or are girls with ADHD misdiagnosed?… It is not a milder disease in females than males.”

Mark Bellgrove

Hot Topic Symposium

The role of noradrenaline in the pathophysiology and treatment of ADHD

This hot topic symposium was opened by Professor Mark Bellgrove (Monash University, Faculty of Medicine, Nursing and Health Sciences, Victoria, Australia) with a stimulating discussion of α2A-adrenergic receptor gene variants and response time variability. Professor Bellgrove presented research suggesting that noradrenergic mechanisms may play an aetiological role in the risk of ADHD, mediated via the influence of the ADRA2A gene. The association between noradrenergic gene variants and ADHD symptomatology was explored further by Dr Li Yang (Peking University Sixth Hospital/Institute of Mental Health, Beijing, China), who also discussed how these genes may predict medication response. Veronica Galvin (Yale School of Medicine, New Haven, CT, USA) then gave a comprehensive review of the literature on α2-adrenergic mechanisms in the prefrontal cortex, explaining how an understanding of brain circuitry at the molecular level can help physicians to understand the effects of ADHD medications. Finally, Dr Jeffrey Newcorn (Icahn School of Medicine, Mount Sinai Hospital, New York, NY, USA) concluded with a thought-provoking overview on the role of noradrenergic drugs in the treatment of ADHD, suggesting that pharmacological treatments that target multiple brain regions may show enhanced efficacy.

Mark Bellgrove: “Heterogeneity in psychiatry is the rule rather than the exception.”

Jeffrey Newcorn: “The treatment that on average shows the largest improvements in impairment may not be the best choice for an individual patient.”

Dr Russel Schachar

Research Consortia Session

Predictors of outcome in ADHD: Symposium organised by CADDRA

Dr Lily Hechtman (Division of Child Psychiatry, McGill University, Montreal Children’s Hospital, Montreal, Quebec, Canada) opened this session by presenting results from a prospective 10- and 15-year follow-up study. She noted that there were 3 groups of adult outcomes: 1) fairly normal (30%) i.e. that they did not significantly differ from matched controls; 2) significant continuing ADHD symptoms (60%); 3) serious psychiatric / antisocial problems (10%), e.g. adults with ADHD that were in and out of psychiatric hospital due to comorbidities such as depression or substance use disorder or who were in prison due to antisocial behaviour. She went on to discuss the results which examined 3 predictor measures (personal characteristics, social-academic parameters and family parameters) compared with 5 outcome measures: emotional adjustment, school performance, police involvement, car accidents, non-medical drug and alcohol use. Results indicated that the negative impact in adulthood could be predicted by IQ, psychiatric comorbidities, and family parameters such as socioeconomic status.

Dr Arunima Roy (Division of Child Psychiatry, McGill University, Montreal Children’s Hospital, Montreal, Quebec, Canada) discussed childhood factors in relation to functional outcomes in adults in the MTA study. Results highlighted that higher IQ in childhood, increased household income and higher parental education and better parenting style (monitoring and supervision) improved functional outcomes in adulthood, whilst greater ADHD symptom severity, childhood comorbidities and parental marital problems had a significant negative impact on functional outcomes. Dr Roy concluded that better adult functional outcomes may be promoted by improving parental monitoring and supervision and providing additional assistance and support to families with low household incomes.

In the final presentation from Dr Russel Schachar (University of Toronto, Department of Psychiatry, Toronto, Canada), he began by explaining that cognitive deficits in ADHD include working memory, reaction time variability, flexibility and temporal processing and that there is an association with differences in neural structure and functional genetics. He went on to discuss why cognitive predictors ought to be studied, and described how response inhibition, working memory, and response variability are possible endophenotypes of ADHD based on their association with the disorders, using results from the McAuley study5 whereby, children with ADHD showed baseline deficits in response inhibition, working memory, and response variability compared with children without ADHD. He also explained that cognitive performance among patients with ADHD improved with age and that within the ADHD group, cognitive performance in childhood and in adolescence did not differ amongst those with persistent, remittent, and partially remittent forms of the disorder. However, he concluded that cognitive predictors are not useful yet to predict who will have ADHD at baseline or predict for persistence and that further research is warranted.

Dr Hechtman: “It is a chronic condition which needs ongoing treatment so treatment should not be time-limited.”

Dr Schachar: “Cognitive predictors are not useful yet to predict who will have ADHD at baseline or predict for persistence.”

Arthur Caye

Hot Topic Symposium

Next generation of longitudinal studies of ADHD

In this hot topic symposium, Professor Margaret Sibley (Florida International University, Miami, FL, USA) opened with a presentation of her ‘top ten recommendations for the design of longitudinal ADHD studies’. This was followed by an engaging preview of results from a meta-analysis investigating predictors of adolescent ADHD, which was presented by Arthur Caye (ADHD Outpatient Program, Hospital de Clínicas de Porto Alegre, Department of Psychiatry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil). Dr Lucy Riglin (Cardiff University, Division of Psychological Medicine and Clinical Neurosciences, Cardiff, UK) then provided an overview of her research on the contribution of ADHD genetic risk variants to population-based developmental trajectories of ADHD symptoms across childhood and adolescence. She reported that adolescents with persistent ADHD symptoms showed higher polygenic risk scores and higher rates of multimorbidity compared with other individuals in a general population. Finally, Professor Barbara Franke (Radboud University Medical Center, Groningen, Amsterdam, the Netherlands) gave a comprehensive presentation on longitudinal data from the NeuroIMAGE study, an international multicentre genetics project, which has generated several publications.

Arthur Caye: “A ‘diagnose and treat’ approach may not be enough. The bad news is that we don’t know enough about prevention…Therefore, the question is – can we find predictors of ADHD?”

Industry Supported Symposia

Getting to the real cost of ADHD: Comparing adults to their siblings
Supported by Medice

In the first industry supported session of the Congress, Professor David Daley (University of Nottingham, Division of Psychiatry and Applies Psychology, Nottingham, UK) and Anne-Mette Lang (Department of Child and Adolescent Psychiatry Research, Aarhus University Hospital, Denmark) presented their research on the cost of ADHD across a spectrum of outcomes. Using the Danish Central Psychiatric Research Register to identify adults diagnosed with ADHD, and comparing these adults with their same-sex siblings without ADHD, Daley and Lang found that individuals with ADHD had higher social care costs; higher in-patient, outpatient and medication costs; paid less income tax; had higher costs related to road traffic accidents and higher costs associated with crime. When all of these costs were combined, the researchers found a total cost difference of €13,561 per individual with ADHD, per year compared with siblings without ADHD. The session concluded with a discussion of the implications of these findings, with a call for policy makers to invest more money into addressing untreated ADHD.

Anne-Mette Lang: “We wanted to measure a broad spectrum of outcomes: occupational, education, crime, health and more.”

Anne-Mette Lang: “One of the advantages of this study over previous studies, is that we were able to look at variables beyond those that are usually captured in insurance databases.”

David Daley: “We can use these data to lobby for better access to interventions, to break these barriers and help individuals with ADHD to live a better life.”

  1. Tung I, Li JJ, Meza JI, et al. Patterns of Comorbidity Among Girls With ADHD: A Meta-analysis. Pediatrics 2016; 138: e20160430.
  2. Dalsgaard S, Mortensen PB, Frydenberg M, et al. Conduct problems, gender and adult psychiatric outcome of children with attention-deficit hyperactivity disorder. Br J Psychiatry 2002; 181: 416-421.
  3. Ottosen C, Petersen L, Larsen JT, et al. Gender Differences in Associations Between Attention-Deficit/Hyperactivity Disorder and Substance Use Disorder. J Am Acad Child Adolesc Psychiatry 2016; 55: 227-234.
  4. Dalsgaard S, Østergaard SD, Leckman JF, et al. Mortality in children, adolescents, and adults with attention deficit hyperactivity disorder: a nationwide cohort study. Lancet 2015; 385: 2190-2196.
  5. McAuley T, Crosbie J, Charach A, et al. The persistence of cognitive deficits in remitted and unremitted ADHD: a case for the state-independence of response inhibition. J Child Psychol Psychiatry 2014; 55: 292-300.