The SCI-DER was developed at the Departments of Psychiatry, Neurobiology, Pharmacology, and Biotechnologies of the University of Pisa by experienced psychiatrists. It includes 49 items exploring "presence" or "absence" of lifetime spontaneous symptoms of depersonalization (DP) organized into four domains: (1) Derealization, (2) Somatopsychic depersonalization, (3) Autopsychic depersonalization, and (4) Affective depersonalization. Items responses are coded in a dichotomous way (yes/no) and total and domain scores are obtained by counting the number of positive answers. When DP symptoms occur during alcohol or drug intake, items are coded as negative. An initial version of the scale was piloted in patients with depersonalization disorder (DPD) and comments were also solicited from researchers with experience in scale construction. The information obtained guided the rephrasing of some questions.
The first domain, Derealization (items 1-9), encompasses all items referring to an altered experience of the external world, and corresponds to the DSM description of derealization. Such an experience is frequently described in terms of visual metaphors (e.g., looking through the fog, a veil between you and the external world). The Somatopsychic depersonalization (items 10-25) domain describes a variety of changes in body experience such as lack of body ownership feelings, feelings of disembodiment, which can range from a nonspecific feeling of not being in the body to out-of-body experiences and autoscopic hallucinations. Somatosensory distortions, usually affecting the size of body parts, or feeling very light, and lack of body sensations or various types of sensory anesthesia (e.g., hunger, thirst, and pain) are also present.
The Autopsychic depersonalization (items 26-41) domain includes the unfamiliarity of the Self in terms of sensation of being an outside observer of one's mental process, not being "in charge" of their own behavior or mental processes, the automaton-like experience and anomalous subjective recall (e.g., the feeling that personal events happened long ago or had already happened, inability to evoke visual memories of people or places).
The Affective depersonalization (items 42-49) domain explores the patient's loss of ability to imbue perceptions with emotional feelings but also comprises the loss of affection, pleasure, fear or disgust to situations previously avoided.
The theoretical framework and all items included were derived from a review of the descriptive psychopathology of DP (Jaspers 1913; Lewis 1931; Mayer-Gross 1935; Roth 1959; Sierra and Berrios 1998, 2001; Simeon et al 2004; Mula et al 2007) which included also a validated instrument for DP, namely the Cambridge Depersonalization Scale (CDS) (Sierra and Berrios 2000). The SCI-DER has some overlap with the CDS but, differently, the CDS was developed to capture frequency and duration of DP experiences in a period covering the last 6 months while the SCI-DER was designed to assess the presence/absence of DP experiences over the lifetime. In this regard, it is worth remarking that our instrument was designed not to be diagnostic, in fact the duration, clustering, and severity of symptoms requested to make a diagnosis according to DSM-IV cannot be determined. Thus, the SCI-DER cannot replace currently used psychiatric interviews, such as the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R) (Bremner et al 1993), but it allows the definition and recognition, together with the typical aspects of DPD, of a wider area of clinical manifestations.

Scoring

See algorithm section, below on this page for how to score the instrument.

Psychometric Properties

Mula M, Pini S, Calugi S, Preve M, Masini M, Giovannini I, Conversano C, Rucci P, Cassano GB.: Validity and reliability of the Structured Clinical Interview for Depersonalization-Derealization Spectrum (SCI-DER). Neuropsychiatr Dis Treat. 2008 Oct;4(5):977-86.

Note: each items is scored as "0" (NO), "1" (YES).
(1) Derealization	sum of items 1 - 9
(2) Somatopsychic depersonalization	sum of items 10 - 25
(3) Autopsychic depersonalization	sum of items 26 - 41
(4) Affective depersonalization	sum of items 42 - 49