Agreeableness and Self-Consciousness as Predictors of Induced Scratching and Itch in Patients with Psoriasis

Psoriasis (PS) is a frequent skin disease accompanied by itch, a symptom that has been shown to be related to depression and self-consciousness. PS patients describe themselves as more agreeable than healthy controls (HC), a trait that might be protective against impulsive scratching.

This study is the first to analyze the relationship between agreeableness and induced scratching and between depression, self-consciousness, and induced itch in PS patients.

Twenty-four PS patients and 24 HC were shown two videos: an itch-inducing experimental video (EV) and a non-itch-inducing control video (CV). Induced itch/scratching was determined by calculating the difference in itch intensity/number of scratch movements between EV and CV. Validated questionnaires were used to measure agreeableness, depression, and self-consciousness.

In accordance with our hypothesis, in PS patients, public self-consciousness was significantly positively associated with induced itch (r = 0.564; p < 0.001), and agreeableness was significantly negatively associated with induced scratching (r = -0.444; p < 0.05). In HC, the relationship between public self-consciousness and induced itch and between agreeableness and induced scratching were positive, but not significant.

This study showed distinct findings for PS patients and HC regarding the relationship between agreeableness and induced scratching. The relationship between public self-consciousness and induced itch was positive in both groups. The distinct finding regarding agreeableness supports the idea that scoring low on this scale might be a protective factor for scratching in PS patients. Future research should investigate mediating factors of the outlined relationships.