For almost half a century feeling unreal has been known as DPD, an abbreviation for Depersonalization Disorder. Now it is about a year since feeling unreal has been renamed. The new fifth edition of the DSM – an official psychiatric Bible - has established a new name - Depersonalization/Derealization Disorder or DDD. Another of the DSM-5’s innovations is narrowing the spectrum of depersonalization by excluding presentations related to substances or medication and other medical conditions. Let’s look closely at what these innovations mean.
1. The Name: Depersonalization versus Depersonalization/Derealization.
Depersonalization and derealization are deeply connected phenomena. Depersonalization refers to the experience of one’s self, where as derealization - to the experience of unreality of the world around. Since the first formulation of DP as a diagnostic category by the DSM-II in1968, the term depersonalization served as a general name for feeling unreal and includes derealization as an associated feature. This tradition was kept through the three generations of DSMs: II, III and IV. The DSM-5 has changed this status quo, adding derealization to depersonalization in the very name of this disorder.
This step appears consistent with the historical frame. Initially depersonalization and derealization are treated as parts of one condition. The first cases of feeling unreal, which are presented by the French otolaryngologist, M. Krishaber, under the name of “cerebro-cardial neuropathy” in 1873, include both unreality of self and unreality of world. Seven years later, in 1880, Swiss thinker Henri Amiel coins the term depersonalization to name his own experiences of unreality both of himself and the world around him.
An entire half a century later, in 1935, British physicians Mapother and Mayer-Gross distinguish derealization as the feeling of unreality of the world around from depersonalization as the feeling of unreality of one’s self. Nevertheless, many researchers and practitioners have kept using depersonalization as a major term, considering derealization as a part of depersonalization. The DSMs have followed this approach. The definition of depersonalization in DSM-II (1968) states that depersonalization “is dominated by a feeling of unreality and of estrangement from the self, body, or surroundings.” Derealization is not mentioned specifically here, but clearly is included in depersonalization as “a feeling of unreality and of estrangement from… surroundings.” The following DSM-III and DSM-IV do employ the term derealization though not as a name of a disorder itself, but as an associated feature of depersonalization disorder.
However, in contrast to the American DSM, the International Classification of Diseases by World Health Organization (ICD) categorizes feeling unreal as depersonalization-derealization syndrome. In this sense, the DSM 5’s move from depersonalization disorder to depersonalization/derealization disorder brings the American classification closer to the International.
If the DSM-5’s name change from DPD to DDD seems a clinically reasonable choice, then the way this change is presented seems more confusing than convincing. The DSM-5 reads, “There is no evidence of any distinction between individuals with predominantly depersonalization versus derealization symptoms. Therefore individuals with this disorder can have depersonalization, derealization or both.” The first statement raises a question: is it at all possible to find individuals – with “depersonalization versus derealization,” or just any individuals - who do not have “any distinction?” Further, this first statement does not provide logical ground for what follows after “therefore” in the conclusive part of the passage. DDD appears to be a terminological preference that also unifies the American and the International psychiatric classifications rather than a principled clinical or theoretical innovation.
2. The cause of depersonalization.
If the previous DSMs carefully avoid speculation regarding causes of depersonalization, the DSM-5 establishes a special criterion related to causality of depersonalization. In general psychiatry infamously struggles with the problem of etiology – causes of disorders. This is especially true for depersonalization. Why does a particular person have a particular form of depersonalization at a particular time? Even though neuroscience, genetics, psychology and other disciplines contribute significantly to understanding of the development of depersonalization, the exact cause of depersonalization remains unclear in the majority of cases. The DSM-5 does not suggest the criterion for a direct cause of depersonalization. The DSM-5 offers the criterion of cause that is an exclusion criterion, namely, causes the presence of which should exclude the diagnosis of depersonalization.
The criterion D (the fourth in five criteria for DDD) specifies that DDD “is not attributable to the physiological effects of substance (e.g. drug of abuse, medication) or another medical condition (e.g. seizures).”
Thus, the DSM-5 excludes two well-known groups which have been traditionally considered as depersonalization. The first excluded group is those numerous cases of depersonalization which appear in relation to using substances, including notorious episodes of post-marijuana or post-psychotomimetics depersonalization. The second excluded group covers conditions which have been historically considered as depersonalization presentations of epilepsy. Classical works on depersonalization describe depersonalization that appears during the course of parietal or temporal lobe epilepsy.
The DSM-5 has narrowed the spectrum of depersonalization, reserving the diagnosis of DDD only for those presentations of feeling unreal which do not have evident connection to other specific conditions or disorders. Different presentations of feeling unreal observed in cases of posttraumatic stress disorder, anxiety, depression, obsessionality and substance-induced disorders, as well as epilepsy or other medical conditions do not meet formal criteria for DDD.
Summarizing the DSM-5 innovations in categorization of depersonalization, one could remark that DDD appears to be a somewhat more “cleaned-up” version of DPD. No breathtaking discovery or revolutionary theoretical reformulation is evident, but rather an attempt to reorganize already known data. It is unlikely that feeling unreal under the name of DDD is becoming more easily diagnosed or more successfully treated than the old DPD.