title: A comparison of brain volume and cortical thickness in excoriation (skin picking) disorder and trichotillomania (hair pulling disorder) in women.
abstract: Skin picking disorder (SPD) and trichotillomania (hair pulling disorder, or HPD) significantly overlap in terms of clinical features. However, few studies have directly compared structural brain data in these disorders. The aim of this study was to compare volumes of brain structures and cortical thickness in patients with SPD and HPD, and determine involvement of fronto-striatal pathways. Seventeen female SPD, 17 HPD and 15 healthy age-matched controls underwent clinical assessment and structural MRI imaging. Group differences were determined in brain volume and cortical thickness, controlling for illness severity. Participants with SPD had greater volume of the ventral striatum bilaterally; and reduced cortical thickness in right hemisphere frontal areas, and greater thickness of the cuneus bilaterally compared to HPD and control participants. HPD participants demonstrated reduced thickness of the right parahippocampal gyrus compared to SPD and control participants. The findings here are partially consistent with previous structural work in SPD, and suggest some differences in the neurobiology of SPD and HPD. The more extensive involvement of the ventral striatum in SPD may suggest greater involvement of the reward system, while the more extensive involvement of the parahippocampal gyrus in HPD may be consistent with the dissociative symptoms often seen in these patients.
authors.affiliation: SU/UCT MRC Unit on Anxiety and Stress Disorders, Cape Town, South Africa. Electronic address: aroos@sun.ac.za.
authors.forename: Annerine
authors.initials: A
authors.lastname: Roos
authors.affiliation: Department of Psychiatry and Behavioral Neuroscience, University of Chicago, USA.
authors.forename: Jon E
authors.initials: JE
authors.lastname: Grant
authors.affiliation: SU/UCT MRC Unit on Anxiety and Stress Disorders, Cape Town, South Africa.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Fouche
authors.affiliation: SU/UCT MRC Unit on Anxiety and Stress Disorders, Cape Town, South Africa; Department of Psychiatry and Mental Health, University of Cape Town, South Africa.
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.affiliation: SU/UCT MRC Unit on Anxiety and Stress Disorders, Cape Town, South Africa.
authors.forename: Christine
authors.initials: C
authors.lastname: Lochner
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D002540:Cerebral Cortex / Q000473:pathology*; D003342:Corpus Striatum / Q000473:pathology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D016728:Self-Injurious Behavior / Q000473:pathology*; D012867:Skin / Q000293:injuries*; D014256:Trichotillomania / Q000473:pathology*
keywords: Fronto-striatal pathway; Hair pulling disorder; Skin picking disorder