Depersonalization disorder is considered to be a common clinical phenomenon and disorder with an enormous gap between prevalence and detection partly due to the common interpretation of depersonalization (DP) being a negligible variant of anxiety and depression. Therefore, we sought to analyze (1) the prevalence rate of DP in a large community sample (n = 5000) according to a recently developed ultra brief two-item depersonalization screener; (2) the associations with depression, anxiety, physical and mental health status; and 93) whether DP contributes independently to the health status beyond anxiety and depression. The prevalence of clinically significant DP was 0.8% (n = 41), and 8.5% (n = 427) endorsed at least one symptom of DP. DP was independently associated with impairment of mental and physical health status as well as with a medical history of any depressive or anxiety disorder. Despite the consistent association of DP with anxiety and depression, the shared variances were small, and DP was clearly separated from symptoms of anxiety and depression in the principal component analysis. Therefore, we conclude that the implementation of depersonalization screening might be recommended.
After anxiety and depression, depersonalization has been considered to be the third most frequent symptom among psychiatric patients (Stewart, 1964). But although depersonalization (DP) is assessed routinely as part of the mental state examination in psychiatric and psychotherapeutic treatment, it is both underdetected and underdiagnosed (Simeon, 2004, Michal and Beutel, 2009, Sierra, 2009 and Stein and Simeon, 2009). According to a recent evaluation of health insurance data of 1.5 million persons, the 1-year prevalence of the diagnosis of the depersonalization–derealization syndrome was only 0.007% (Michal et al., 2010a, Michal et al., 2010b and Michal et al., 2010c). This prevalence contrasts sharply with epidemiological studies reporting rates of 0.8–2% for clinically significant DP in the general population (Hunter et al., 2004 and Michal et al., 2009). Reluctance of patients to report spontaneously about DP is one factor; another factor is the health care providers' relative lack of awareness, due to the common interpretation of DP as a negligible variant of anxiety and depression (Simeon, 2004 and Sierra, 2009). This neglect of DP however, may also have an impact on the treatment and outcome of depression and anxiety disorders. Several studies found that DP co-occurring with depression and anxiety is an index of disease severity, chronicity and poor treatment response (Katerndahl, 2000 and Mula et al., 2007). Recently, we have shown in a large community sample that depersonalization severity was independently associated with suicidal ideation beyond depression and anxiety (Michal et al., 2010b).
In order to overcome the lack of awareness for DP, questionnaires or structured interviews are extremely helpful (Edwards and Angus, 1972). For clinical and neurobiological research purposes, Sierra and Berrios (2000) developed the Cambridge Depersonalization Scale (CDS), measuring the complex phenomenology of depersonalization and derealization experiences comprehensively with 29 items (Sierra and Berrios, 2000). This scale is currently the most detailed and valid measure describing and quantifying depersonalization and derealization, but the CDS seems too costly for routine screening purposes. Therefore an ultra-brief two-item scale for DP was developed from the CDS, i.e., the two-item version of the Cambridge Depersonalization Scale (CDS-2, Michal et al., 2010c). The scoring format of the CDS-2 was adopted from the most common ultra-brief screeners for depression and anxiety (PHQ-2, Löwe et al., 2005; and GAD-2, Löwe et al., 2009) in order to establish an easy and brief screening for DP.
