Summary: Researchers report ADHD and conduct disorder exhibit similar, overlapping changes in the brain.
Source: Karolinska Institute.
In both ADHD and emotional instability disorders (e.g. borderline and antisocial personality disorder as well as conduct disorder in children), the brain exhibits similar changes in overlapping areas, meaning that the two types of conditions should be seen as related and attention should be paid to both during diagnosis. This according to researchers at Karolinska Institutet behind a new study published in Molecular Psychiatry. The results can lead to a broader treatment for both conditions.
Clinical attention has long been paid to the fact that individuals with ADHD also demonstrate emotional problems, such as chaotic emotional responses, anxiety and depression. Yet the relationship between ADHD and impaired emotional regulation has not been identified, even if theories have been proposed that both conditions are rooted in a dysfunction in how the brain controls its information processing.
A new study by researchers at Karolinska Institutet in Sweden substantiated the hypothesis by showing how both ADHD and a form of emotional instability trait (conduct disorder trait in children) exhibit similar, overlapping changes in the brain. The study included more than 1,000 adolescents.
“We can call them sibling conditions, since they both involve partly overlapping underlying brain mechanisms, and therefore attention should be paid to both dimensions during diagnosis,” says Predrag Petrovic, associate professor at the Department of Clinical Neuroscience at Karolinska Institutet and consultant psychiatrist at North Stockholm Psychiatry.
It was with the help of structural brain imagery (MR) that the team was able to show how both ADHD and conduct disorder traits in adolescents manifested themselves in the form of reduced brain volume and surface area in parts of the frontal lobe and nearby regions. The affected parts of the brain were generally overlapping, but the researchers also found changes that were specifically related to ADHD symptoms or symptoms seen in conduct disorder. The study also included behavioural experiments that demonstrated both conditions.
“These results are important not least for the patients with emotional instability, since in many cases they are treated with scepticism and feel frustrated at not being taken seriously,” says Dr Petrovic. “We now show that this is related to changes in the brain that resemble those that have been observed in patients with ADHD, which can lead to a broader understanding and better diagnosis.”
The study was part of the IMAGEN-project, an EU-funded collaboration amongst several European countries that aims towards a better understanding of how the brain and behaviour develop.
The hope is that the study will not only lead to better diagnoses but also to better treatments, where people with an ADHD diagnosis can receive special therapy to help them better handle their emotions.
“We also need to do more research to understand if central stimulant medication used for ADHD can also produce positive results for people with emotional instability disorders,” says Dr Petrovic.
Funding: The study was financed with grants from several bodies, including the European Commission, the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas), the Swedish Research Council, the National Institute for Health Research (NIHR), the Bundesministerium fur Bildung und Forschung, the Swedish Society for Medical Research (SSMF) and Karolinska Institutet.
Source: Karolinska Institute
Publisher: Organized by NeuroscienceNews.com.
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Original Research: Abstract for “Distinct brain structure and behavior related to ADHD and conduct disorder traits” by Frida Bayard, Charlotte Nymberg Thunell, Christoph Abe?, Rita Almeida, Tobias Banaschewski, Gareth Barker, Arun L. W. Bokde, Uli Bromberg, Christian Buchel, Erin Burke Quinlan, Sylvane Desrivie?res, Herta Flor, Vincent Frouin, Hugh Garavan, Penny Gowland, Andreas Heinz, Bernd Ittermann, Jean-Luc Martinot, Marie-Laure Paille?re Martinot, Frauke Nees, Dimitri Papadopoulos Orfanos, Tomas Paus, Luise Poustka, Patricia Conrod, Argyris Stringaris, Maren Struve, Jani Penttila?, Viola Kappel, Yvonne Grimmer, Tahmine Fadai, Betteke van Noort, Michael N. Smolka, Nora C. Vetter, Henrik Walter, Robert Whelan, Gunter Schumann and Predrag Petrovic in Molecular Psychiatry. Published August 14 2018.
Distinct brain structure and behavior related to ADHD and conduct disorder traits
Attention-Deficit/Hyperactivity Disorder (ADHD) and conduct disorder (CD) exemplify top-down dysregulation conditions that show a large comorbidity and shared genetics. At the same time, they entail two different types of symptomology involving mainly non-emotional or emotional dysregulation. Few studies have tried to separate the specific biology underlying these two dimensions. It has also been suggested that both types of conditions consist of extreme cases in the general population where the symptoms are widely distributed. Here we test whether brain structure is specifically associated to ADHD or CD symptoms in a general population of adolescents (n = 1093) being part of the IMAGEN project. Both ADHD symptoms and CD symptoms were related to similar and overlapping MRI findings of a smaller structure in prefrontal and anterior cingulate cortex. However, our regions of interest (ROI) approach indicated that gray matter volume (GMV) and surface area (SA) in dorsolateral/dorsomedial prefrontal cortex and caudal anterior cingulate cortex were negatively associated to ADHD symptoms when controlling for CD symptoms while rostral anterior cingulate cortex GMV was negatively associated to CD symptoms when controlling for ADHD symptoms. The structural findings were mirrored in performance of neuropsychological tests dependent on prefrontal and anterior cingulate regions, showing that while performance on the Stop Signal test was specifically related to the ADHD trait, delayed discounting and working memory were related to both ADHD and CD traits. These results point towards a partially domain specific and dimensional capacity in different top-down regulatory systems associated with ADHD and CD symptoms.