Misidentification syndromes in schizophrenia: case reviews with implications for classification and prevalence.

Misidentification syndromes represent false, delusionally-based identification of self and/or others. These are variants of the Capgras Syndrome. Although the frequency of misidentification syndromes in schizophrenic populations has not yet been established, the authors believe this syndrome is more prevalent than previously described. Seven of twenty-five (28%) consecutive patients admitted to a chronic clozapine unit with a variant of misidentification syndrome will be described. Their symptoms are categorised according to traditional classification, and Silva's proposed nomenclature. Problems inherent in these classifications are discussed. The need for a more systematic classification of misidentification syndromes is emphasised. Longitudinal studies of misidentification syndrome, and the development of a standardised assessment tool for clinicians who treat chronically psychotic patients, are encouraged.