Cross-cultural adaptation and validation of the Cambridge Depersonalisation Scale

The Cambridge Depersonalisation Scale (CDS) is a self-rating questionnaire constructed to capture the frequency and duration of depersonalization symptoms over the last six months. The instrument has proved to be valid and reliable and can be useful in both clinical and neurobiological research. This paper presents the Spanish adaptation and validation of the CDS. The study was carried out in two stages. First, we developed the Spanish version of the CDS by means of a cross-cultural adaptation methodology. Second, the CDS was tried on a sample of 130 subjects: 77 patients meeting DSM-IV-TR criteria for schizophrenia, 35 with depression disorders and 18 with anxiety disorders. Scores were compared against clinical diagnoses (gold standard). Furthermore, all the subjects of the study were administered the following: Dissociation Experiences Scale (DES), Positive and Negative Syndrome Scale (PANSS), Beck's Depression Inventory (BDI), and the Hamilton Anxiety Rating Scale (HARS). 38 patients (29.2 %) had depersonalization symptoms. The scale showed high internal consistency (Cronbach's alpha > 0.9 and split-half reliability > 0.8) and a test-retest reliability of 0.391. Convergent validity was 0.65 (p < 0.001) and discriminant validity was 0.308 (p < 0.05). The area under the ROC curve was 0.94. A cut-off of 71 appears to be most useful (sensitivity and specificity were 76.3 % and 89.1 %, respectively). The Spanish version of the CDS has good reliability and validity, similar to the original instrument.