Italian (cross cultural) adaptation and validation of the Cambridge Depersonalization Scale (CDS).

Dear Editor Depersonalization (DP), long a complex and obscure subject of clinical psychiatry, has become a recurrent topic of psychopathology in the last 10 years. Often accompanied by derealization, a threatening sense of unreality in the environment, which also appears unfamiliar, DP is defined as an experience of ‘unreality’ and ‘detachment’ from the self. But in clinical practice DP can have various and shaded forms and it is still unclear whether it should be considered a symptom or a syndrome. DP occurs on a continuum from transient episodes to a symptom complex in a primary psychiatric diagnosis, or as a primary mental disorder that tends to run a chronic course (Simeon et al. 1998). It seems that it can co-occur with virtually any psychiatric condition. Major nosographic systems in turn have emphasized the anxiety component or saw the condition closer to a dissociative one. In the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition-Text Revision (DSM-IV TR) (American Psychiatric Association, 2000), DP is an independent condition inside dissociative disorders, ‘the DP Disorder’. In International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) (World Health Organization, 1992), it is a neurotic condition whose occurrence as an isolated syndrome is uncommon. Current epidemiological data show a prevalence of clinically significant DP (DP disorder in DSM-IV TR) in general population of approximately 1–2%, similar to prevalence found for common mental disorders, such as bipolar and obsessive-compulsive disorder (Michal et al. 2009). The first systematic review on epidemiology reports that prevalence rates of transient symptoms of DP in general population range between 26 and 74% (Hunter et al. 2004). Despite this prevalence, available instruments assessing DP (Table 1) (Mula et al. 2007a) often lack psychometric properties, as a consequence of a theoretical gap or of different theoretical models. Many of the instruments are not specific, having only a few items detecting DP experiences at an explicit level according to the classic repartition (self, bodily and allopsychic). They fail to address either the phenomenological complexity or the frequency and the intensity of the phenomenon. As for the specific ones, all were developed to measure severity of DP symptoms within a defined time frame (6–12 months) and proved useful in monitoring treatment response, but they have shown dubious validity (e.g. Dixon’s Depersonalization Scale (DDS) has only been used in few studies and includes clinical features not considered part of the syndrome by the classical descriptors; Jacobs and Bovasso Depersonalization Scale (JBS) leaves out some important cognitive complaints) (Sierra & Berrios, 2000). The Structured Clinical Interview for DP-Derealization Spectrum (SCI-DER), developed on a spectrum model of DP lifetime experiences, showed very good reliability and validity, but with 49 items may take quite a long time to perform. Among all the instruments only the DES scale is translated into Italian. Based on a comprehensive study of DP phenomenology, the Cambridge Depersonalization Scale (CDS) (Sierra & Berrios, 2000) was designed to measure parameters of intensity and frequency within the previous 6 months. The questionnaire showed high internal consistency, good reliability (Cronbach’s alpha and split-half reliability of 0.89 and 0.92, respectively), and convergent validity when compared with the DP subscale of the DES (0.80) (Sierra & Berrios, 2000; Sierra et al. 2005). A factor analysis performed in 2005 by Sierra et al. extracted four factors accounting for 73.30% of the variance. A second one in 2008 (Simeon et al. 2008) used a larger sample and appeared to split up the factor labeled ‘anomalous body experiences’ in the first study, into two components: ‘unreality of self’ and ‘perceptual alterations’. * Address for correspondence: Dr V. Migliorini, M.D., CSM (Centro di Salute Mentale) Anagni, via San Giorgetto, 03012 Anagni, Frosinone (FR), Italy. (Email: [email protected]) Epidemiology and Psychiatric Sciences (2012), 21, 221–226. © Cambridge University Press 2012 LETTER TO THE EDITOR doi:10.1017/S2045796011000850