The assessment of "prodromal schizophrenia": unresolved issues and future directions.

Because of the novelty of research with clinical high risk ("prodromal") patients, many unresolved issues exist concerning how the prodromal state is defined and measured. Data are presented from the Recognition and Prevention (RAP) program at the Zucker Hillside Hospital to address several outstanding questions. Baseline attenuated positive symptoms were rated in 42 putatively prodromal patients in the RAP program using the Scale of Prodromal Symptoms (SOPS). Followup data of 6 months or more were available on 34 of these subjects; 9 of these (26.5%) developed psychotic disorders. Patients who developed psychosis had significantly higher SOPS positive symptom scores at baseline than those who did not. Various thresholds, using both total SOPS positive symptom scores and highest single item score, significantly predicted transition to psychosis, which calls into question appropriate cutoffs for the distinction between health, prodromal status, and psychosis. The SOPS positive symptom "conceptual disorganization" was found to be significantly related to disorganized behavior but not to other positive symptoms or to psychotic outcome, suggesting the importance of examining dimensions of psychopathology. The dimensional quantification of prodromal symptom severity may be an important direction for future studies of the assessment of at-risk states.