The Self-screen-Prodrome as a short screening tool for pre-psychotic states

Abstract

Background: Early detection of psychosis is an important issue in current research. Early intervention helps to improve the outcome of the disorder. Therefore, a comprehensive examination in large populations, necessary as it might be, is economically almost not feasible. A screening via self-report is more practicable as it helps focus on individuals with high symptom loads.

Aim: To examine aspects of validity of the Self-screen-Prodrome (SPro) as a new screening tool for prodromal states of psychosis in a military sample.

Method: 938 Swiss conscripts were assessed with the SPro, the Eppendorf Schizophrenia-Inventory (ESI) and the Symptom-Checklist-90-Revised (SCL-90-R). Conscripts with potential psychosis-like pathology (T-transformed Severity Index of the SCL-90-R-subscales Psychoticism [PSYC] and Paranoid Ideation [PARA]≥63) were compared with those not meeting the criteria of this condition (non-cases).

Results: Both groups (cases and non-cases) showed significant differences in their mean scores on SPro and ESI, although only the SPro had satisfactory effect sizes. In hierarchic logistic regression models the SPro turned out to be highly predictive for caseness while ESI-scales were not significant. A cut-off score of ≥2 on the SPro subscale for psychotic risk (SPro-Psy-Risk) was found to identify caseness best with a sensitivity of 74% and a specificity of 61%.

Conclusion: The SPro has proven to be a valid and very economic screening tool for general and prodromal pathology in large populations.