A significant association between anxiety and depersonalization has been found in healthy controls and psychiatric patients irrespective of underlying conditions. Although patients with depersonalization disorder (DPD) often have a history of severe anxiety symptoms, clinical observations suggest that the relation between anxiety and depersonalization is complex and poorly understood. Using relevant rating scales, levels of anxiety and depersonalization were assessed in 291 consecutive DPD cases. ‘High’ and ‘low’ depersonalization groups, were compared according to anxiety severity. Correlation and multivariate regression analyses were also used to assessed the contribution of anxiety to the phenomenology and natural course of depersonalization. A low but significant association between depersonalization and anxiety (as measured by Beck's Anxiety Inventory) was only apparent in those patients with low intensity depersonalization, but not in those with severe depersonalization. Levels of anxiety did not seem to make specific contributions to the clinical features of depersonalization itself, although DPD patients with high anxiety seem characterised by additional non-specific perceptual symptoms. The presence of a ‘statistical dissociation’ between depersonalization and anxiety adds further evidence in favour of depersonalization disorder being an independent condition and suggests that its association with anxiety has been overemphasized.
It has been known for more than a century that depersonalization and anxiety states are often closely associated. Indeed, most patients complaining of ‘feelings of unreality’, originally described by Krishaber (1873), also suffered from episodes of paroxysmal anxiety, reminiscent of panic attacks. Echoing those early observations, Roth (1959) emphasised the presence of anxiety symptoms in patients with chronic depersonalization and coined the term 'phobic-anxiety depersonalization syndrome', to define a specific anxiety disorder, which had depersonalization and agoraphobia as its central manifestations.
Subsequent studies have also documented a significant association between anxiety and depersonalization across the severity spectrum of depersonalization. Thus, significant correlations have been found in non-clinical populations (Trueman, 1984); in psychiatric in-patients regardless of primary diagnosis (Noyes et al., 1977), and in patients with depersonalization disorder (Baker et al., 2003). In fact, of all emotional states, anxiety has been found to be the strongest predictor of depersonalization (Simeon et al., 2003). Of all anxiety manifestations accompanying depersonalization, studies have emphasised social anxiety and panic attacks (Noyes et al., 1992, Toni et al., 1996 and Michal et al., 2005). Indeed, depersonalization (including derealization) has always been considered one of the constituent symptoms of a panic attack, occurring in up to 60% of patients (Swinson and Kuch, 1990). While in most such patients, the experience of depersonalization is limited to the duration of the attack, in others it outlasts its duration and can become persistent (Hollander et al., 1989). A recent study on 104 patients with panic disorder found that 20% met criteria for depersonalization disorder (Mendoza et al., 2011). In fact, a common clinical observation in patients with depersonalization disorder is the clustering of panic attacks around the time of onset of depersonalization, subsequently becoming less frequent or absent as depersonalization becomes chronic and predominant. A similar inverse association has also been found in psychophysiological studies. Thus, as compared with anxiety disorder patients, DPD patients reporting similarly high levels of subjective anxiety, show attenuation of autonomic sympathetic responses (Kelly and Walter, 1968, Sierra et al., 2002 and Sierra et al., 2006). The above observations suggest that the relation between anxiety and depersonalization is complex and poorly understood. The following is a systematic analysis of the relationship between the two conditions in a large series of patients with DPD. In particular we addressed two related questions: 1-Does the presence of comorbid anxiety impose a qualitative or quantitative change on the depersonalization experience? 2- Can anxiety account for the presence of adjunct symptoms, which often accompany depersonalization such as tinnitus, dizziness, or hallucinatory-like experiences?
