Diagnostic Efficiency of the Rorschach Perceptual and Thinking Index (PTI) in discriminating Ultra High Risk (UHR) Adolescent helpseekers from non-UHR

Introduction. Rorschach Perceptual and Thinking Index (PTI) is higher in adolescents at ultra-high risk for psychosis (UHR) in comparison with adolescents non-UHR patients, evaluated with the Structured Interview for Prodromal/Psychosis-risk Symptoms (SIPS). However, the diagnostic efficiency of Rorschach PTI has never been examined. The aim of this study is to evaluate the diagnostic efficiency of the Rorschach PTI in discriminating UHR from non-UHR adolescents helpseekers. Methods. A sample of 155 patients, 47% males, (14-18 years) were included and referred to the clinic for Anxiety and Mood Disorders in Adolescence (Department of Psychiatry of Sant'Andrea Hospital in Rome). Subjects met diagnostic criteria for the following DSM-5 diagnoses: Anxiety Disorders (30%), Depressive Disorders (40%), Bipolar Disorders (15%), Obsessive-Compulsive Disorders (10%); UHR patients were 19. The sample was evaluated with the Rorschach (calculated according to the standard Comprehensive System Method) and with the SIPS. The cut-off for the PTI index was fixed to 3. Results. Rorschach PTI reported the current efficiency diagnostic indexes: Overall Correct Classification (OCC) was 0,87; Sensitivity (SENS) was 0,63; Specificity (SPEC) was 0,90; Positive Predictive Power was 0,48; Negative Predictive Power was 0,94; Cohen’s k was 0,47. Conclusions. Rorschach shows a moderate ability to differentiate UHR from non-UHR adolescent patients, especially in the identification of the subjects that do not present UHR.