The examination of magnetic resonance imaging findings in patients with skin picking disorder

Introduction: Skin picking disorder (SPD) is characterized by repetitive and compulsive picking behaviour leading to tissue damage. Neuropsychological studies in SPD reported impairments in response inhibition, emotion regulation, increased emotional reactivity and increased impulsivity. Little is known about the neurobiology of SPD. Previous functional magnetic resonance imaging (fMRI) findings about SPD showed abnormalities in regions about emotion regulation and executive functions, such as frontal regions, basal ganglia, amigdala and insula. This study aims to investigate connectivity abnormalities during resting state. Methods: This study included 10 drug naive SPD patients and 10 healthy controls (matched on age, gender and years of education). The patients did not have any comorbidities. All participants underwent fMRI scans during resting state. Experiments were performed on a 3 T MRI scanner. Data were preprocessed using Statistical Parametric Mapping software.Seed-to-voxel functional connectivity analysis was performed using the CONN toolbox. Results: SPD patients displayed increased negative correlation in functional connectivity in the two clusters of right middle frontal gyrus (p=0.000003, MNIpeak coordinates: 44 -50 -14; cluster sizes= 885 voxel ve p=0.000033, MNI peak coordinates: -10 -80 -14;cluster sizes = 678 voxel) and right angular gyrus (p=0.000172, MNI peak coordinates: 18 -42 -6; cluster sizes=571 voxel). Discussion: Previous fMRI studies about SPD were either task-based or during symptom provocation. To our knowledge, this is the first resting-state fMRI study of individuals with SPD. By applying seed-to-voxel connectivity analysis with CONN, we found altered functional connectivity in regions of executive network and default mode network. These results suggest that abnormal connectivity in the executive network and default mode network might play a crucial role in the neurobiology of SPD.