Dear Editor:
We read with great interest the article on delusional misidentification syndromes (DMS) by Atta and colleagues, which appeared in the September issue of Psychiatry 2006.1 Their overview of this topic is timely, given the increasing interest of delusional misidentification in psychiatry and other behavioral sciences. There are a few points that we want to address.
With regard to treatment of delusional misidentification syndrome (DMS), we agree with the authors that there is a paucity of controlled studies. The authors appear to accept the view that symptoms of DMS are very refractory to psychopharmacological treatment. However, in our meta-analytic study2 of 104 DMS cases published in the literature from 1957 to 1994 where information regarding treatment with antipsychotic medications was available, 70 cases had shown improvement, while 34 cases did not improve. The interested reader may find that study useful, since it provides a comprehensive analysis of the psychopharmacological treatment of DMS as well as an overview of other treatments for DMS and antedate current psychopharmacologic practice in which the newer generation antipsychotics and other strategies become the mainstay of treatment of psychoses.
Although the authors did not explicitly discuss it, the two cases presented by them highlight another important management issue, namely that of aggression. There is presently an extensive and growing literature implicating DMS as being associated either directly or indirectly with violent behaviors. For example, in one of our meta-analytic studies,3 we identified 80 cases of persons with DMS published in the psychiatric literature who had manifested either verbal or physical aggression. A more recent review4 of this problem also supports the view that aggression may be an important management issue in a significant proportion of persons affected by DMS.
Atta and colleagues1 mentioned Hirstein and Ramachandran's5 view on Capgras syndrome and its potential association with limbic system dysfunction, a thesis that relies on the well-known finding that those suffering from DMS are likely to be emotionally close to the delusionally misidentified objects (persons). Nonetheless, an aspect of Capgras syndrome that continues to resist adequate explanation is the relative specificity to usually a few delusionally misidentified objects. In our experience, the delusional misidentified object is a subset of a much larger universe of emotionally significant objects that are frequently available for the delusional person to misidentify. It is unclear whether the chosen misidentified object becomes misidentified because it is affectively familiar and/or physically familiar to the delusional person.
The view that psychiatric conditions related to DMS could be intrinsically associated with abnormalities of memory was postulated early in the 20th century and remains one of the most important potential explanations for Capgras syndrome, a point that we think must be emphasized as a leading paradigm in DMS research. The work of Hirstein and Ramachandran5 highlight a recent attempt to understand DMS by focusing on memory deficits as an important issue.
With regards,
J. Arturo Silva, MD
Private Practice, Forensic Psychiatry, San Jose, California
Gregory B. Leong, MD
Clinical Professor of Psychiatry, University of Washington School of Medicine, Seattle, Washington
Robert Weinstock, MD
Clinical Professor of Psychiatry, University of California, Los Angeles
Contributor Information
J. Arturo Silva, Private Practice, Forensic Psychiatry, San Jose, California.
Gregory B. Leong, Clinical Professor of Psychiatry, University of Washington School of Medicine, Seattle, Washington.
Robert Weinstock, Clinical Professor of Psychiatry, University of California, Los Angeles.
References
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