ABSTRACT
Background: There is increasing evidence that people with attention-deficit/hyperactivity disorder (ADHD) are impaired in emotion regulation, but psychophysiological and functional MRI data on emotion processing in adult patients with ADHD are scarce. We investigated the neural correlates of reappraisal as one of the most efficient emotion-regulation strategies. Methods: We included 30 adult patients with ADHD and 35 healthy controls in our study. We applied a well-established reappraisal paradigm in functional MRI and assessed behavioural emotion-regulation strategies with standardized questionnaires. We hypothesized that patients with ADHD would demonstrate impaired reappraisal related to reduced activations in the frontoparietal cognitive control network. Results: Despite our hypothesis, we found no significant activation differences in the neural reappraisal network between patients with ADHD and controls. As well, both groups revealed similar reappraisal success on the immediate behavioural ratings in the scanner. Interestingly, patients with ADHD revealed significantly increased activations in the dorsal and ventral anterior cingulate cortex (ACC) compared to controls when viewing negative > neutral pictures. These ACC activations were significantly correlated with the prevalence of habitual use of reappraisal in patients with ADHD only. Limitations: Patients withdrew medication only 24 hours before the experiment; we investigated negative, but not positive, emotion processing and regulation. Conclusion: Although emotion dysregulation is regarded as a core symptom of ADHD, explicit reappraisal does not seem to be impaired in adult patients. However, increased activation of the ACC implies stronger implicit emotion regulation induced by negative stimuli. This might be explained by emotional hyperresponsivity in patients with ADHD compared with controls.
Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnostic imaging , Emotional Regulation , Frontal Lobe/diagnostic imaging , Gyrus Cinguli/diagnostic imaging , Parietal Lobe/diagnostic imaging , Adult , Attention Deficit Disorder with Hyperactivity/physiopathology , Attention Deficit Disorder with Hyperactivity/psychology , Case-Control Studies , Female , Frontal Lobe/physiopathology , Functional Neuroimaging , Gyrus Cinguli/physiopathology , Humans , Magnetic Resonance Imaging , Male , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Parietal Lobe/physiopathology , Young AdultABSTRACT
OBJECTIVES: Attention-deficit/hyperactivity disorder (ADHD) is closely linked to the dysregulation of dopaminergic and noradrenergic neurotransmission in the fronto-striatal neural network, including the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC). Additionally, increasing evidence supports the involvement of the glutamatergic system in the pathophysiology of ADHD. Impulsivity, a core symptom in patients with ADHD, has been repeatedly associated with glutamatergic neurotransmission, and pharmacological treatment of ADHD has been shown to reduce glutamate levels in the prefrontal cortex. METHODS: We investigated glutamate levels in the ACC and the DLPFC in 30 adults with ADHD and 30 healthy controls using single-voxel proton magnetic resonance spectroscopy on a 3T scanner. RESULTS: The ADHD group showed a significant increase in glutamate in the ACC compared to controls, no significant differences in metabolites were observed in the DLPFC. Overall, glutamate levels in the ACC were positively correlated with ADHD symptomatology, especially hyperactivity and impulsivity symptoms. CONCLUSIONS: Increased levels of glutamate in the ACC, which were positively correlated with hyperactivity and impulsivity, support the hypothesis that dysfunctional glutamatergic neurotransmission is at least partially responsible for ADHD symptomatology. Modulation of glutamatergic neurotransmission might therefore be a promising avenue for future pharmacological interventions.
Subject(s)
Attention Deficit Disorder with Hyperactivity/metabolism , Attention Deficit Disorder with Hyperactivity/physiopathology , Glutamic Acid/metabolism , Gyrus Cinguli/physiopathology , Impulsive Behavior , Psychomotor Agitation , Adult , Case-Control Studies , Female , Gyrus Cinguli/metabolism , Humans , Magnetic Resonance Spectroscopy , Male , Middle Aged , Prefrontal Cortex/metabolism , Prefrontal Cortex/physiopathology , Synaptic Transmission , Young AdultABSTRACT
Emotional dysregulation (ED) is being increasingly recognized as a core feature of attention-deficit/hyperactivity disorder (ADHD), but the pathophysiological underpinnings remain unclear. In this study, we provide meaningful electrophysiological evidence of ED in adult patients with ADHD (n = 39) compared to healthy controls (n = 40) by exploring the electrophysiological correlates of the emotion regulation strategies reappraisal, distraction, and expressive suppression. Event-related potentials (ERPs) were recorded during passive viewing of neutral and negative images, as well as during emotion regulation. The patients with ADHD exhibited increased frontal late positive potential (LPP) amplitudes during passive viewing of the aversive images and during emotion regulation. Compared with the healthy controls, a subgroup of medication-naïve patients with ADHD (n = 25) also exhibited larger centroparietal LPP amplitudes and provided more negative ratings of the aversive and neutral images. Both the frontal and centroparietal LPP amplitudes were associated with ADHD symptom severity. However, no significant deficit in LPP modulation during emotion regulation was found. These findings strongly support the clinical observation of increased emotional responsivity toward negative stimuli and difficulty during the implementation of emotion regulation strategies and thus encourage the implementation of emotion regulation modules in the treatment of adult patients with ADHD.
