Do psychiatric patients fit their diagnoses? Patterns of symptomatology as described with the biplot.

Systems of psychiatric diagnosis have been regularly criticized for their low reliability and their inability to fit accurately the kinds of patients coming for treatment. To explore the reasons for these problems, this study utilizes a new method, the biplot, for defining groups of similar patients and the relationships of these groups to key symptom clusters. Using this technique to analyze data from a representative sample of first admissions for psychiatric disorder, results showed: a) symptom clusters representing the classical diagnostic categories, mania, schizophrenia, neurotic depression, and psychotic depression, were readily identified; b) however, only a few patients were clustered near these traditional syndromes. These findings suggest that although syndromes do exist that fit traditional diagnostic categories, the vast majority of patients fall between these syndromes, having characteristics from several of them. For most patients, forcing the diagnostician to choose among the categories requires an arbitrary decision that may contribute to dissatisfaction in the diagnostician who recognizes how misleading the diagnosis can be.