Characterising resting-state functional connectivity in a large sample of adults with ADHD

AbstractAttention-deficit/hyperactivity disorder (ADHD) is a common childhood psychiatric disorder that often persists into adulthood. While several studies have identified altered functional connectivity in brain networks during rest in children with ADHD, few studies have been performed on adults with ADHD. Existing studies have generally investigated small samples. We therefore investigated aberrant functional connectivity in a large sample of adult patients with childhood-onset ADHD, using a data-driven, whole-brain approach. Adults with a clinical ADHD diagnosis (N=99) and healthy, adult comparison subjects (N=113) underwent a 9-minute resting-state fMRI session in a 1.5T MRI scanner. After elaborate preprocessing including a thorough head-motion correction procedure, group independent component analysis (ICA) was applied from which we identified six networks of interest: cerebellum, executive control, left and right frontoparietal and two default-mode networks. Participant-level network maps were obtained using dual-regression and tested for differences between patients with ADHD and controls using permutation testing. Patients showed significantly stronger connectivity in the anterior cingulate gyrus of the executive control network. Trends were also observed for stronger connectivity in the cerebellum network in ADHD patients compared to controls. However, there was considerable overlap in connectivity values between patients and controls, leading to relatively low effect sizes despite the large sample size. These effect sizes were slightly larger when testing for correlations between hyperactivity/impulsivity symptoms and connectivity strength in the executive control and cerebellum networks. This study provides important insights for studies on the neurobiology of adult ADHD; it shows that resting-state functional connectivity differences between adult patients and controls exist, but have smaller effect sizes than existing literature suggested

A qualitative and quantitative study of self-reported positive characteristics of individuals with ADHD

Research in Attention-deficit/hyperactivity disorder (ADHD) has had a clear focus on treatment and the dysfunction in specific situation associated with the condition. However, self-report, observational and anecdotal evidence indicates that there are also positive aspects associated with ADHD. Research on the potential positive features in individuals with an ADHD diagnosis is still limited, especially studies with larger representative samples. Here we performed qualitative research to identify positive aspects and strengths associated with ADHD in a large convenience sample from the Dutch organization for people with ADHD, dyslexia and dyscalculia. We sent out open-ended questionnaires to the members of the organization, asking what they consider to be positive aspects of their ADHD. From the responses of individuals with ADHD (n = 206), we extracted 116 codes, which were assigned to thirteen subthemes, which in turn led to five themes. These themes were: Creativity, Being dynamic, Flexibility, Socio-affective skills, and Higher-order cognitive skills. Core symptoms of ADHD such as impulsivity and hyperactivity were also considered positive aspects of ADHD by a minority of participants. After showing our results to a group of additional individuals with ADHD (focus group) they confirmed the identified positive aspects of ADHD. They also helped us with the interpretation of our findings and mentioned certain positive aspects to be a consequence of living with ADHD (being open minded and being honest). In conclusion, experiencing positive aspects seems to be common in ADHD as almost all participants reported positive aspect of ADHD, these aspects cover many different domains. Awareness about ADHD's strengths might help individuals with ADHD and their environment to better cope with, accept or embrace their diagnosis and for example make educational or occupational choices that fit them well. To incorporate these positive aspects in the understanding of ADHD, future research should focus on quantifying strengths in ADHD, and on investigating the link between these aspects and clinical characteristics and how this new knowledge can be implemented in psychoeducation and find its way to education and occupational settings

Enlarged striatal volume in adults with ADHD carrying the 9-6 haplotype of the dopamine transporter gene DAT1

The dopamine transporter gene, DAT1 (SLC6A3), has been studied extensively as a candidate gene for attention-deficit/hyperactivity disorder (ADHD). Different alleles of variable number of tandem repeats (VNTRs) in this gene have been associated with childhood ADHD (10/10 genotype and haplotype 10-6) and adult ADHD (haplotype 9-6). This suggests a differential association depending on age, and a role of DAT1 in modulating the ADHD phenotype over the lifespan. The DAT1 gene may mediate susceptibility to ADHD through effects on striatal volumes, where it is most highly expressed. In an attempt to clarify its mode of action, we examined the effect of three DAT1 alleles (10/10 genotype, and the haplotypes 10-6 and 9-6) on bilateral striatal volumes (nucleus accumbens, caudate nucleus, and putamen) derived from structural magnetic resonance imaging scans using automated tissue segmentation. Analyses were performed separately in three cohorts with cross-sectional MRI data, a childhood/adolescent sample (NeuroIMAGE, 301 patients with ADHD and 186 healthy participants) and two adult samples (IMpACT, 118 patients with ADHD and 111 healthy participants; BIG, 1718 healthy participants). Regression analyses revealed that in the IMpACT cohort, and not in the other cohorts, carriers of the DAT1 adult ADHD risk haplotype 9-6 had 5.9 % larger striatum volume relative to participants not carrying this haplotype. This effect varied by diagnostic status, with the risk haplotype affecting striatal volumes only in patients with ADHD. An explorative analysis in the cohorts combined (N = 2434) showed a significant gene-by-diagnosis-by-age interaction suggesting that carriership of the 9-6 haplotype predisposes to a slower age-related decay of striatal volume specific to the patient group. This study emphasizes the need of a lifespan approach in genetic studies of ADHD

Prevalence and cost of ADHD comorbidity

Do individuals with ADHD more often suffer from depression, anxiety, substance abuse or severe obesity, than individuals without ADHD? Are there differences between men and women in how often this is the case? Does having ADHD in addition to one of these conditions result in higher health care costs

D 9.3– Report on WP1 findings on prevalence and costs of comorbidity: CoCA, Comorbid Conditions of Attention deficit / hyperactivity disorder H2020 - 667302

We have disseminated the findings that up until now have been published by partners in WP1. First, we have focussed on the publication on costs of comorbidity, that were published by Libutzki et al. in the journal European Psychiatry, May 2019. Simultaneous with the advanced online publication of the paper (26 February 2019), we released a press release and an infographic to disseminate the findings internationally. This news was picked up by multiple media in The Netherlands and Germany, and was well received by ADHD patient organisations. Second, we have created a set of slides to summarize the five published articles reporting on the prevalence of comorbid conditions with ADHD across the lifespan, stratified by sex. These slides will be shared with CoCA partners for dissemination, and are used to create a webinar to share with our target audiences. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 667302. This report reflects only the author’s views.This report is for the EU. They will put it somewhere, where everybody interested could potentially read it

D 9.3– Report on WP1 findings on prevalence and costs of comorbidity:CoCA, Comorbid Conditions of Attention deficit / hyperactivity disorder H2020 - 667302

We have disseminated the findings that up until now have been published by partners in WP1. First, we have focussed on the publication on costs of comorbidity, that were published by Libutzki et al. in the journal European Psychiatry, May 2019. Simultaneous with the advanced online publication of the paper (26 February 2019), we released a press release and an infographic to disseminate the findings internationally. This news was picked up by multiple media in The Netherlands and Germany, and was well received by ADHD patient organisations. Second, we have created a set of slides to summarize the five published articles reporting on the prevalence of comorbid conditions with ADHD across the lifespan, stratified by sex. These slides will be shared with CoCA partners for dissemination, and are used to create a webinar to share with our target audiences. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 667302. This report reflects only the author’s views.This report is for the EU. They will put it somewhere, where everybody interested could potentially read it