The study is an empirical comparison of three indexes in the Rorschach Comprehensive System developed for the assessment of psychotic functioning, the Schizophrenia Index (SCZI), the Ego Impairment Index (EII-2) and the Perceptual Thinking Index (PTI) in a Serbian sample. In spite of the conceptual differences, these indexes significantly overlap. The study investigated the validity of these three indexes in differentiating psychotic from non-psychotic psychiatric inpatients. Results indicated that all three indexes were successful in differentiating the two groups, with the PTI showing the greatest effectiveness. The results were interpreted as providing evidence for the utility of the Rorschach in evaluating psychosis and for its use in a cross-cultural context.