A latent profile analysis of age of onset in pathological skin picking

Pathological Skin Picking (PSP) may begin at any age, but the most common age of onset is during adolescence. Age of onset is a potentially useful clinical marker to delineate subtypes of psychiatric disorders. The present study sought to examine empirically defined age of onset groups in adults with PSP and assess whether groups differed on clinical characteristics.

Participants were 701 adult respondents to an internet survey, who endorsed recurrent skin picking with tissue damage and impairment. Latent profile analysis (LPA) was conducted to identify subtypes of PSP based on age of onset. Then subgroups were compared on demographic and clinical characteristics.

The best fitting LPA model was a two-class solution comprised of a large group with average age of onset in adolescence (n = 650; 92.9% of the sample; Mean age of onset = 13.6 years) and a small group with average onset in middle adulthood (n = 50; 7.1% of the sample; Mean age of onset = 42.8 years). Relative to the early onset group, the late onset group reported significantly less focused picking, less skin picking-related impairment, lower rates of co-occurring body-focused repetitive behaviors, and trends towards reduced family history of PSP. Individuals in the late onset group also reported increased rates of comorbid depression, anxiety and posttraumatic stress disorder, and were more likely to report that initial picking onset seemed related to or followed depression/anxiety and physical illness.

Findings suggest the presence of two distinct PSP age of onset groups: (1) an early onset group with average onset in adolescence, clinical characteristics suggestive of greater picking-related burden and familiality, and a profile more representative of the general PSP population; and (2) a late onset group with average onset in middle adulthood, increased co-occurring affective and trauma conditions, and initial onset associated with or following other mental health and physical problems. Future replication is needed to assess the validity and clinical utility of these subgroups.