Differentiating adolescents at clinical high risk for psychosis from psychotic and non-psychotic patients with the Rorschach

This study was designed to assess cognitive functioning in a clinical sample of adolescents with heterogeneous psychiatric diagnoses, with a specific focus on patients at clinical high risk (CHR) for psychosis. The sample comprised 22 patients identified at CHR for psychosis, 67 psychotic and 187 non-psychotic, non-CHR patients. Neuropsychological assessment was conducted as part of the clinical examination and treatment, including Wechsler Intelligence Scale for Children (WISC)-III and/or Wechsler Adult Intelligence Scale (WAIS)-III measures of verbal comprehension, perceptual organisation, working memory and processing speed, Wisconsin Card Sorting Test (WCST) measures of executive function, and the Rorschach Comprehensive System measures of perceptual and thinking accuracy. Patients at CHR for psychosis did not significantly differ from other patient groups in terms of intellectual or executive functions. The Rorschach Perceptual Thinking Index (PTI) distinguished patients at CHR for psychosis from those diagnosed as having non-psychotic disorders, but not from those diagnosed as psychotic. Our results suggest perceptual and thought disturbance as an important indicator of vulnerability to psychosis.