Assessing illness-related stress in psoriasis: the psychometric properties of the Psoriasis Life Stress Inventory.

The purpose of the present study was to undertake a clinical and psychometric reappraisal of the Psoriasis Life Stress Inventory (PLSI). Total PLSI score was inversely related to age of onset of psoriasis, but bore no significant relationship to duration or to clinical severity. Similarly, patients' stress score did not differ with regards to the nature of their current treatment, to their beliefs as to what was responsible for exacerbation or improvement of their condition, or to the patients' gender. Factor analysis extracted two factors which suggested that the psychosocial impact of psoriasis results from stress associated with: (i) engaging in anticipatory/avoidance coping behavior that is effected to limit the sociocognitive intrusiveness of psoriasis; and (ii) stress resulting from patients' beliefs or actual experiences of being evaluated by others solely on the basis of their skin. The internal reliability of the scale can be improved by the deletion of three items. Revision of the PLSI is recommended to render it psychometrically and clinically acceptable for use in the UK.