A self-administered version of a brief measure of suffering: First aspects of validity

Background: Measuring the impact of illness is important for several reasons. Recently, a new instrument was introduced using a pictorial approach in measuring the perception of suffering caused by illness: the Pictorial Representation of Illness Measure (PRISM). The aim of the present study was to introduce a self-administered version of PRISM and to provide some first data on its validity. Method: A postal survey was conducted in subjects with the chronic depigmentation disorder vitiligo. Participants were members of the German vitiligo association. The response rate was 60.6%. Data of 333 respondents completing the PRISM were used for analysis. Besides illness-related measures, psychological variables were assessed with the following instruments: Satisfaction with Life Scale (SWLS), five-item version of the Mental Health Inventory, adaptation of the Skindex-29, a quality-of-life measure for skin diseases. Results: Only 2.9% did not fill in the PRISM. Self-illness separation correlated as predicted with some illness-related variables. The distance was significantly larger in subjects whose depigmentation was no longer spreading. Significant correlations were also found with mental health (0.50), satisfaction with life (-0.28), perceived impairment of outward appearance (-0.65), and the Skindex subscales 'emotions' (-0.66) and 'functioning' (-0.67). Conclusion: Data suggest that PRISM can be self-administered. Measures of convergent validity confirm the usefulness of the new measure.