Assessment of PIC and MMPI scales in adolescent psychosis: a caution

This study investigated the sensitivity of two frequently used multidimensional instruments--the Personality Inventory for Children (PIC) and the Minnesota Multiphasic Personality Inventory (MMPI)--in assessing psychotic states in adolescents. This issue arose as a result of the fact that the PSY scale on the PIC was constructed and cross-validated only on samples of children between the ages of 5 and 12 years. T-score comparisons between psychotic and nonpsychotic samples were performed, as well as Pearson correlations between PIC Psychosis (PSY) and MMPI Schizophrenia (Sc) scale T-scores. T-score comparisons indicated no significant differences between the groups on either PSY or Sc. A nonsignificant relationship between PSY and Sc scale elevations was also found. These results suggest the need for a profile-analytic approach to PIC and MMPI interpretation in identifying psychotic symptomatology in adolescents rather than PSY or Sc T-score elevation in isolation.