Interoception abnormalities and skin-picking disorder: Systematic review and narrative synthesis of preliminary evidence.

A growing body of research suggests that disrupted interoception plays an important role in various mental disorders, including Obsessive-Compulsive and Related Disorders. However, interoceptive abnormalities in Skin Picking Disorder (SPD) remain unexplored. This study aimed to evaluate and synthesize existing evidence regarding interoceptive disruptions in SPD, adopting a broad definition of interoception encompassing certain types of skin-mediated signals. We searched five databases (PubMed, Scopus, EBSCO, Web of Science, Embase) for articles reporting associations between SPD and any interoceptive modality/dimension. Citation tracking was also conducted. The database search identified 118 articles, and citation tracking additional nine. Eight distinct studies, involving 1338 participants (462 with SPD) met the inclusion criteria. Findings indicated disrupted affective touch processing in SPD. Pain sensitivity did not differentiate individuals with SPD from controls. Limited evidence indicated reduced cardiac interoceptive accuracy and lower emotional awareness in SPD, alongside a link between heightened reliance on bodily signals and decreased control over picking. A post-hoc analysis suggested possible disruptions in itch processing. Overall, preliminary evidence indicates interoceptive disruptions in SPD.