[A case of late-onset schizophrenia with the predominant symptom of delusional perception of the color of food].

Herein, we report the case of a woman in her late 60s with late-onset schizophrenia in which the predominant symptom was delusional perception of the color of food based on a delusional "rule of colors" system constructed by the patient. This paranoid type schizophrenia is considered a core type of schizophrenia in which first-rank Schneiderian symptoms are initially exhibited. After approximately four years, the chronic phase, characterized by a poor social function, is reached. In this respect, the main psychopathological characteristics of the present case of late-onset schizophrenia are the same as those of typical cases of schizophrenia in young patients. In this study, the patient's delusional "rule of colors" system is analyzed according to Matussek's theory of delusional perception.