Validity and reliability of the Dissociative Symptoms Scale in Italy: Preliminary findings.

The Dissociative Symptoms Scale (DSS) is a 20-item self-reported measure of dissociation, recently validated by Elizabeth B. Carlson and her research Group in the US. The DSS addresses four clusters of dissociative symptoms, namely Depersonalization/ Derealization, Memory Gaps, Sensory Misperceptions, and Cognitive-Behavioral Reexperiencing. The DSS was translated in Italian and back-translated in English, and the translation was discussed with the original Authors of the measure until a consensus on the Italian translation was reached. The approved translation of the DSS and other measures on attachment, trauma, and dissociation were administered to a sample of 428 adult volunteers from the community and to 82 psychiatric inpatients. Both classical test theory and item response theory were used to examine the psychometric properties of the DSS in Italy. The DSS showed good reliability (alpha=.88, split-half r=.83; AIC=.28). The goodness-of-fit indexes for its original factor structure were satisfactory. IRT analyses showed that the a-values of the DSS items were all above 1, thus each DSS item was discriminating for the construct of dissociation. DSS scores were positively and significantly correlated with childhood and adult trauma, with psychoform and somatoform dissociation scores, and with fearful attachment. The findings support the view that the Italian translation of the DSS is a valid and reliable measure of dissociation.