Reliability and descriptive validity of PSE syndromes.

Despite extensive research use of the Present State Examination (PSE), the validity of classification based on PSE data has not been studied extensively. We have examined a consecutive series of functional psychiatric admissions using the PSE and systematically gathered clinical and demographic data in order to study not only the reliability but the descriptive (construct) validity of classification based on PSE data. We have found that the PSE can be used in a psychiatric hospital to reliably describe and classify schizophrenic and affective syndromes with considerable descriptive validity in terms of clinical and demographic variables. We believe that this type of validity is an important step in establishing validity of clinical disease entities. The interrelationship among different kinds of validity (descriptive, concurrent, predictive) might provide clinical disease concepts with more definitive validity.