Neuropsychological relationships in paranoid schizophrenia with and without delusional misidentification syndromes. A comparative study

Delusional misidentification syndromes (DMSs) and schizophrenia are strongly associated, since the former occur predominantly in the context of paranoid schizophrenia. However, the possible underlying neuropsychological relationships between DMSs and paranoid schizophrenia have not been thoroughly investigated. The aim of the present study was to investigate whether DMSs in paranoid schizophrenia are associated with a distinct neuropsychological substrate indicative of differential bilateral frontal and right hemisphere dysfunction. We compared two matched groups of paranoid schizophrenic patients with (N = 22) and without (N = 22) DMS(s) on a battery of neuropsychological tests assessing mainly frontal and right hemisphere functions. No statistically significant differences were detected between the two groups. Our findings are indicative of a bilateral frontal and right hemisphere dysfunction of equal severity in both DMS and non-DMS patients with paranoid schizophrenia.