Hyperactivity/restlessness is associated with increased functional connectivity in adults with ADHD: a dimensional analysis of resting state fMRI.

BACKGROUND: Adult attention-deficit/hyperactivity disorder (ADHD) is a serious and frequent psychiatric disorder of multifactorial pathogenesis. Several lines of evidence support the idea that ADHD is, in its core, a disorder of dysfunctional brain connectivity within and between several neurofunctional networks. The primary aim of this study was to investigate associations between the functional connectivity within resting state brain networks and the individual severity of core ADHD symptoms (inattention, hyperactivity, and impulsivity). METHODS: Resting state functional magnetic resonance imaging (rs-fMRI) data of 38 methylphenidate-naïve adults with childhood-onset ADHD (20 women, mean age 40.5 years) were analyzed using independent component analysis (FSL's MELODIC) and FSL's dual regression technique. For motion correction, standard volume-realignment followed by independent component analysis-based automatic removal of motion artifacts (FSL's ICA-AROMA) were employed. To identify well-established brain networks, the independent components found in the ADHD group were correlated with brain networks previously found in healthy participants (Smith et al. PNAS 2009;106:13040-5). To investigate associations between functional connectivity and individual symptom severity, sex, and age, linear regressions were performed. RESULTS: Decomposition of resting state brain activity of adults with ADHD resulted in similar resting state networks as previously described for healthy adults. No significant differences in functional connectivity were seen between women and men. Advanced age was associated with decreased functional connectivity in parts of the bilateral cingulate and paracingulate cortex within the executive control network. More severe hyperactivity was associated with increased functional connectivity in the left putamen, right caudate nucleus, right central operculum and a portion of the right postcentral gyrus within the auditory/sensorimotor network. CONCLUSIONS: The present study supports and extends our knowledge on the involvement of the striatum in the pathophysiology of ADHD, in particular, in the pathogenesis of hyperactivity. Our results emphasize the usefulness of dimensional analyses in the study of ADHD, a highly heterogeneous disorder. TRIAL REGISTRATION: ISRCTN12722296 ( https://doi.org/10.1186/ISRCTN12722296 ).

Regulation of sadness via acceptance or suppression in adult Attention Deficit Hyperactivity Disorder (ADHD).

Emotion dysregulation is a recognized symptom of adult Attention Deficit Hyperactivity Disorder (ADHD). The aim of this study is to induce sadness in adults suffering from ADHD and to investigate the impact of emotion regulation strategies on sadness intensity, and psychophysiological measures. Thirty-six adults diagnosed with ADHD were randomly assigned to either expressive suppression (SUPP) or acceptance (ACC) of emotion. Sadness was induced using a film clip. Participants estimated the intensity of sadness and the perception of being overwhelmed with emotion before (T1), immediately after (T2) and 2 min after the film (T3). Physiological measures were obtained. Sadness induction was effective in both conditions. The perception of being overwhelmed with emotion increased between T1 and T2 in both conditions, but persisted until T3 only in the expressive suppression condition whereas a decrease was observed in the acceptance condition. In ADHD expressive suppression of sadness seems to be associated to a prolonged recovery from the perception of being overwhelmed with emotion. Emotion-regulation via acceptance in contrast appears to allow faster recovery from the perception of being overwhelmed with emotion. To our knowledge, this is the first study to identify suppression as a critical mediator between an induced emotion and delayed recovery from emotional reactions in adult ADHD.