Near the beautiful castle in Örebro, Sweden 2018, we kicked off our new network of enthusiastic researchers working in the ADHD research field. This network consists of early and mid-career researchers who work on topics related to ADHD across the lifespan and have a link with one of the IMpACT (International Multicenter persistent ADHD CollaboraTion) projects.
Our network has the aim to unite the knowledge of the individual young researchers in the field of ADHD to boost the further development of our field. Furthermore, we aim to facilitate the exchange of students and offer them international experiences in our research labs. Our final aim is to have closer ties between the members. This way it will become easier to replicate research findings, collaborate and brainstorm with researchers that work on related topics.
In Frankfurt 2019 we decided to start working towards a first collaborative project. More about this will follow soon.
Our work can be followed here on ‘mind-the-gap.live’ by our tag ‘impactnextgen’
Virtual-reality (VR) can be defined as an interactive computer-generated experience that can be similar to the real world or fantastical1. For instance, in a VR environment, a person is able to virtually live in the artificial world by looking and moving around it, as well as interacting with virtual characters or items2. Nowadays there are different kinds of VR environments, mainly used for entertainment purposes (e.g. video-games) or professional training (e.g. aviation, military training etc.)3. VR tools usually range from a headset (head-mounted displays with a small screens in front of the eyes), to proper full-scale rooms with bigger screens and special equipment to increase the augmented reality experience.
VR has been recently investigated as a potential treatment for different metal health problems or psychiatric disorders such as social anxiety4, specific phobias5, post-traumatic stress disorder (PTSD)6, or persecutory delusions7. The key assumption behind the use of VR tools in mental health practice, relies in the fact that, in VR settings, individuals can repeatedly experience and learn appropriate coping strategies in a controlled environment8,9. For instance, knowing that the exposure is not real, allows people to face difficult situations and learn therapeutic strategies which they can then adopt in the real world.
..but how those VR tools can be used for the treatment of ADHD?
Recent evidence shows that VR can help enhance some of the core therapeutic challenges of ADHD such as attention, problem solving and managing impulsive behaviours10. For example, using VR can create virtual scenarios that can reward and empower skills such as response inhibition and emotional control10. One of the most commonly used scenarios is the class-room environment, which can introduce life-like distractions to asses children’s behaviour in an ecologically-based setting 10-11. In this virtual environment children with ADHD may be more able to use the trial-and-error instructional strategies to train learning skills11. For instance, in these VR settings, children with ADHD can also learn strategies to use in the real world without experiencing failures due to their experiences at school, making them more willing to accept the private feedback of the VR teacher.
Although VR ca be potentially used in ADHD treatment, is still an experimental procedure that needs more research to assess its validity. Also, there are still some concerns regarding potential side effects of long-term VR exposure, such as headaches, seizures, nausea, fatigue, drowsiness, disorientation, apathy, and dizziness10. Overall, despite its therapeutic potential, more studies are needed to assess its long-term treatment efficacy as well as the efficacy of VR environments compared to other non-pharmacological treatments already available for ADHD.
Isabella Vainieri and Jonna Kuntsi
Isabella Vainieri is a PhD student at the Social, Genetic & Developmental Psychiatry Centre at King’s College London.
Jonna Kuntsi is Professor of Developmental Disorders and Neuropsychiatry at King’s College London.
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Rizzo A’, Shilling R. Clinical Virtual Reality tools to advance the prevention, assessment, and treatment of PTSD. Eur J Psychotraumatol. 2017;8(sup5):1414560. Published 2017 Jan 16. doi:10.1080/20008198.2017.1414560
Freeman, D., Bradley, J., Antley, A., Bourke, E., DeWeever, N., Evans, N., Černis, E., Sheaves, B., Waite, F., Dunn, G., Slater, M., & Clark, D. (2016). Virtual reality in the treatment of persecutory delusions. British Journal of Psychiatry, 209, 62-67.
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Slater M, Rovira A, Southern R, Swapp D, Zhang J, Campbell C, et al. Bystander responses to a violent incident in an immersive virtual environment. PLoS One 2013; 8: e52766.
Bashiri A, Ghazisaeedi M, Shahmoradi L. The opportunities of virtual reality in the rehabilitation of children with attention deficit hyperactivity disorder: a literature review. Korean J Pediatr. 2017;60(11):337–343.
Bioulac S, Lallemand S, Rizzo A, Philip P, Fabrigoule C, Bouvard MP. Impact of time on task on ADHD patient’s performances in a virtual classroom. Eur J Paediatr Neurol. 2012;16:514–521
Have you ever thought that ADHD and autism could perhaps be the same disorder? – Or have you thought that they are way too different, two different planets in the psychiatric universe? Researchers do not agree on this. We know that both ADHD and autism are neurodevelopmental conditions with onset in childhood and that they share some common genetic factors, however, they appear with quite different phenotypical characteristics. We also know that people with ADHD or autism have an increased risk of getting other psychiatric disorders, so-called comorbidities, and smaller studies have shown that individuals with ADHD or autism get different psychiatric disorders, and at a different degree.
How can we utilize this knowledge about different psychiatric comorbidities between ADHD and autism? How can we get closer to an answer to this question; are ADHD and autism similar or different conditions? By using large datasets; unique population-based registries in Norway, we wanted to compare the pattern of psychiatric comorbidities in adults diagnosed with ADHD, autism or both disorders. In addition, we wanted to compare the pattern of genetic correlations between ADHD and autism for the same psychiatric traits, and for this, we exploited summary statistics from relevant genome-wide association studies.
In the registries, we identified 39,000 adults with ADHD, 7,500 adults with autism and 1,500 with both ADHD and autism. We compared these three groups with the remaining population of 1.6 million Norwegian adult inhabitants without either ADHD or autism. The psychiatric disorders we studied were anxiety, bipolar, depression, personality disorder, schizophrenia spectrum (schizophrenia) and substance use disorders (SUD).
Interestingly, we found different patterns of psychiatric comorbidities between ADHD and autism, overall and when stratified by sex (Fig.1). These patterns were also reflected in the genetic correlations, however, only two of the six traits showed a significant difference between ADHD and autism (Fig.2).
Figure 2A: The pattern of prevalence ratios of psychiatric comorbidity in adults with ADHD or autism observed in this study (ADHD; n=38,636, autism; n=7,528). Psychiatric conditions are highly prevalent in both ADHD and ASD, with schizophrenia being most prevalent in ASD and antisocial personality disorders in ADHD. Figure from Solberg et al. 2019, CC-BY-NC-ND.
Figure 2B: Genetic correlations (rg) calculated from genome wide association studies. Genetic correlations are also high with both disorders, with especially high correlations between ADHD and alcohol dependence, smoking behavior and anti-social behavoiur. Major depressive disorder has high genetic correlations with both ADHD and autism. Figure from Solberg et al. 2019, CC-BY-NC-ND.
Figure 2. Left: The pattern of prevalence ratios of psychiatric comorbidity in adults with ADHD or autism observed in this study (ADHD; n=38,636, autism; n=7,528). Right: genetic correlations (rg) calculated from genome wide association studies. Psychiatric conditions are highly prevalent in both ADHD and ASD, with schizophrenia being most prevalent in ASD and antisocial personality disorders in ADHD. Genetic correlations are also high with both disorders, with especially high correlations between ADHD and alcohol dependence, smoking behavior and anti-social behavoiur. Major depressive disorder has high genetic correlations with both ADHD and autism. Figure from Solberg et al. 2019, CC-BY-NC-ND.
The most marked differences were found for schizophrenia and SUD. Schizophrenia was more common in adults with autism, and SUD more common in adults with ADHD. Associations with anxiety, bipolar and personality disorders were strongest in adults with both ADHD and autism, indicating that this group of adults suffers from more severe impairments than those with ADHD or autism only. The sex differences in risk of psychiatric comorbidities were also different among adults with ADHD and ASD.
In conclusion, our study provides robust and representative estimates of differences in psychiatric comorbidities between adults diagnosed with ADHD, autism or both ADHD and autism. With the results from analyses of genetic correlations, this finding contributes to our understanding of these disorders as being distinct neurodevelopmental disorders with partly shared common genetic factors.
Clinicians should be aware of the overall high level of comorbidity in adults with ADHD, autism or both ADHD and autism, and the distinct patterns of psychiatric comorbidities to detect these conditions and offer early treatment. It is also important to take into account the observed sex differences. The distinct comorbidity patterns may further provide information to etiologic research on biological mechanisms underlying the pathophysiology of these neurodevelopmental disorders.
This study was done at Stiftelsen Kristian Gerhard Jebsen Centre for Neuropsychiatric disorders, University of Bergen, Norway, and published OnlineOpen in Biological Psychiatry, April 2019, with the title:
Berit Skretting Solberg is a PhD-candidate at the Department of Biomedicine/Department of Global Health and Primary Care, University of Bergen, Norway. She is also a child- and adolescent psychiatrist/adult psychiatrist. She is affiliated with the CoCa-project, studying psychiatric comorbidities in adults with ADHD or autism, using unique population-based registries in Norway.
After the first project on subcortical brain volumes in ADHD, published in Lancet Psychiatry in 2017 , ENIGMA-ADHD now analysed cortical data of 2246 people with a diagnosis of ADHD and 1713 people without, aged between four and 63 years old. The data came from 37 research groups from around the world. FreeSurfer (imaging software) parcellations of thickness and surface area of 34 cortical regions were compared between cases and controls in 3 separate age groups; children, adolescents and adults.
Subtle differences only in the group of children were found. The childhood effects were most prominent and widespread for the surface area of the cortex. More focal changes were found for thickness of the cortex. All differences were subtle and detected only at a group level, and thus these brain images cannot be used to diagnose ADHD or guide its treatment.
These subtle differences in the brain’s cortex were not limited to people with the clinical diagnosis of ADHD: they were also present – in a less marked form – in youth with some ADHD symptoms. This second finding results from a collaboration between the ENIGMA-ADHD Working Group and the Generation-R study from Rotterdam, which has brain images on 2700 children aged 9-11 years from the general population. The researchers found more symptoms of inattention to be associated with a decrease in cortical surface area. In a third study, using the NeuroImage data from Nijmegen and Amsterdam, familial effects on those regions that showed case-control differences were investigated. Siblings of those with ADHD showed changes to their cortical surface area that resembled their affected sibling. This suggests that familial factors such as genetics or shared environment may play a role in brain cortical characteristics.
‘We identified cortical differences that are consistently associated with ADHD combining data from many different research groups internationally. We find that the differences extend beyond narrowly-defined clinical diagnoses and are seen, in a less marked manner, in those with some ADHD symptoms and in unaffected siblings of people with ADHD. This finding supports the idea that the symptoms underlying ADHD may be a continuous trait in the population, which has already been reported by other behavioural and genetic studies.’ In the future, the ADHD Working Group, which is led by Martine Hoogman and Barbara Franke from the Radboudumc in Nijmegen, hopes to look at additional key features in the brain- such as the structural connections between brain areas – and to increase the representation of adults affected by ADHD, in whom limited research has been performed to date.
The ADHD Working Group is one of over 50 working groups of the ENIGMA Consortium, in which international researchers pull together to understand the brain alterations associated with different disorders and the role of genetic and environmental factors in those alterations. For more information about ENIGMA-ADHD please visit our website http://enigma.usc.edu/ongoing/enigma-adhd-working-group/ or contact Martine Hoogman martine.hoogman (at) radboudumc.nl
Attention-deficit/hyperactivity disorder (ADHD) is considered a complex disorder caused by underlying genetic and environmental risk factors. To make it even more complex, environmental factors can influence the expression of genes. This is called epigenetics.
Given the large proportion of the heritability of ADHD still to be explained, there is a growing interest in the epigenetic mechanisms that modulate gene expression. microRNAs (miRNA) are small parts in the human genome that do not code for genes, but instead regulate the expression of other genes by promoting the degradation or suppressing the translation of those target genes. miRNA therefore provide a means to integrate effects of genetic and environmental risk factors.
The human genome encodes more than 2500 different miRNAs, the majority of which are expressed in the brain. miRNAs are known to be involved in the development of the central nervous system and in many neurological processes including synaptic plasticity and synaptogenesis. Given the limited accessibility of the human brain for studying epigenetic modifications, miRNA profiling in peripheral blood cells is often used as a non-invasive proxy to study transcriptional and epigenetic biosignatures, and to identify potential clinical biomarkers for psychiatric disorders.
We recently investigated the role of microRNAs in ADHD at a molecular level, by conducting the first genome-wide integrative study of microRNA and gene expression profiles in blood of individuals with ADHD and healthy controls. We identified three miRNAs (miR-26b-5p, miR-185-5p and miR-191-5p) that have different expression levels in people with ADHD, compared to those without ADHD. When we investigated downstream miRNA-mediated mechanisms underlying the disorder this provided evidence that aberrant expression profile of these three miRNA may underlie changes in the expression of genes related with myo-inositol signaling. This mediates the biological response of a large number of hormones and neurotransmitters on target cells. We also found that these miRNAs specifically targeted genes involved in neurological disease and psychological disorders.
These findings show that epigenetic modifications through microRNAs play a role in ADHD, and provide novel insights into how these miRNA-mediated mechanisms contribute to the disorder. In the future, these miRNAs may be used as peripheral biomarkers that can be easily detected from blood, as is shown in the figure.
The mechanism through which miRNAs modify gene expression is complex and dynamic. Therefore, future studies are required to provide deeper insights into the epigenetic mechanisms underlying ADHD, and to identify specific molecular networks that may be crucial in the development of the disorder.
Cristina Sánchez-Mora et al. Epigenetic signature for attention-deficit/hyperactivity disorder: identification of miR-26b-5p, miR-185-5p, and miR-191-5p as potential biomarkers in peripheral blood mononuclear cells, Neuropsychopharmacology, volume 44, pages 890–897 (2019).
Cristina Sánchez-Mora is postdoctoral researcher at the Psychiatry, Mental Health and Addictions group at Vall d’Hebron Institut de Recerca (VHIR). Her research is part of the CoCA consortium that investigates comorbid conditions of ADHD
Emerging evidence from research studies suggests that physical activity can improve attention, brain function and well-being. In an attempt to understand more about the beneficial effects of high-intensity exercise, we recently conducted a study on the effect of PHysicalActivity on Brain function (PHAB study). We examined whether cycling at a high intensity for 20 minutes would improve brain-activity (electroencephalography; EEG) measures of attention and focus during computerised tasks. We also aimed to investigate whether some individuals, for example those who are physically fit, would benefit more or less from exercise.
Does high-intensity exercise improve attention?
Participants (young adult men) were invited to our research centre, where they completed computer tasks while we recorded their brain activity. In the first task, they were asked to respond to letter ‘X’ following an ‘O’, but not to respond if another letter was presented after an ‘O’. Participants performed the task both before and after exercise and rest, and so we were able to test if their brain activity changed after exercise.
We found that an attention measure called the “P3” was enhanced after exercise but not after rest. This suggests that the intense exercise session led to improvements in their attention. These improvements in attention from exercise were equal across participants, regardless of how physically fit they were.
The participants also performed two subsequent computer tasks, but we did not find improvements after exercise in these tasks. We believe that the beneficial effects of exercise may have worn off by the time that they performed these tasks.
One often hears that the first written description of ADHD stems from the book of the German physician Melchior Adam Weikard “Der Philosophische Arzt” (translated: “The philosophical doctor”) published in 1775. Other well-known old descriptions include for example George F. Still’s description from 1902 published in the Lancet, and Alexander Crichton’s description from 1798. However, this year a Brazilian research group published a report where they claim that the first know description of ADHD, or at least ADHD-like behavior, might be more than 2000 years old!*
The philosopher Theophrastus was a former pupil of Plato and Aristotle who lived in ancient Greece. In approximately 319 years BC he wrote “The Characters”, which essentially is a collection of texts that describes the behavior of 30 stereotypical characters where each character is devoted 10-15 phrases. One of these characters, “the obtuse man”, is an adult man who is described to have both inattention symptoms (forgets important appointments) and hyperactivity symptoms (tires out his children while playing). In addition, “the obtuse man” also has sleep problems and has problems with planning, which both are more common among individuals with ADHD than among those without.
Despite that it can be argued that the behavior of the “the obtuse man” is not a perfect description of typical ADHD, it is still interesting that the oldest known description of ADHD-like behavior describes these symptoms in an adult, in contrast to the later descriptions of ADHD-like behavior that are about children with these symptoms. Moreover, Theophrastus’ more than 2000-year-old text further supports that ADHD (and other psychiatric disorders) has been a part of human life as long as we have been humans.
*Victor MM, Bruna SdS, Kappel DB, Bau CH, Grevet EH. Attention-deficit hyperactivity disorder in ancient Greece: The Obtuse Man of Theophrastus. Aust N Z J Psychiatry. Jun 2018;52(6):509-513.
Tor-Arne Hegvik is medical doctor who is doing research on ADHD and its co-morbidities as a part of the CoCA project: https://coca-project.eu/