Brief report Psychophysiological correlates of patients with delusional misidentification syndromes and psychotic major depression Charalabos C. Papageorgiou a, * , Basil Alevizos a , Erricos Ventouras b , Evagelos Kontopantelis c , Nikolaos Uzunoglu c , George Christodoulou a a Department of Psychiatry, University of Athens, Eginition Hospital, 74 Vas. Sophias Ave., Athens 11528, Greece b Department of Medical Instrumentation Technology, Technological Educational Institution of Athens, Athens 12210, Greece c Department of Electrical and Computer Engineering, National Technical University of Athens, Athens 15773, Greece Received 8 January 2003; received in revised form 28 May 2003; accepted 2 June 2003 Abstract Background: Psychotic major depression (PMD) and delusional misidentification syndromes (DMS) exhibit cognitive deficits. Since the P300 component of event-related potentials (ERPs) provides valuable information concerning cognition, we studied this component of ERPs in DMS and PMD patients. Methods: Nine patients with DMS, 15 patients with PMD, and 11 healthy controls, matched for age, sex and educational level, were tested using the auditory P300 component of ERPs. Results: Both patient groups showed significant reductions in P300 amplitude at the right frontal region, while DMS group showed significant attenuation of the P300 amplitude at the right parietal area. P300 latency was significantly prolonged in the central midline brain region in the DMS group. Limitations: The smallness of the sample size and the hypothetical post-hoc assignation of psychological function to regional activation. Conclusion: PMD and DMS patients may share similar psychophysiological alterations connected to the right frontal region, mediating automatic processes, while DMS are associated with dysfunction of effortful mechanisms and allocation of attentional resources involving the interhemispheric and right parietal circuitry. D 2003 Elsevier B.V. All rights reserved. Keywords: Delusional misidentification syndromes (DMS); Event-related potentials (ERPs); P300; Psychotic major depression (PMD); Working memory (WM) 1. Introduction The delusional misidentification syndromes (DMS) including the Capgras, the Fre ´goli, and intermetamor- phosis syndrome, are characterized by a misidentifi- cation delusion of the self or others (Christodoulou, 1991). A close association in various aspects exists between DMS and psychotic major depression (PMD). Both entities are presented with delusions (Munro, 2000) and dopamine overactivity is an essential bio- logical substrate of delusional symptoms for both disorders (Roane et al., 1998; Wood et al., 2002), while antipsychotic medication is effective in treating this symptomatology (Mulsant et al., 1997; Zanker, 2000). The right hemispheric function and/or inter- 0165-0327/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0165-0327(03)00136-8 * Corresponding author. Tel.: +30-210-728-9117; fax: +30-210- 72-42032. E-mail address: panchris@otenet.gr (C.C. Papageorgiou). www.elsevier.com/locate/jad Journal of Affective Disorders 81 (2004) 147 – 152