The Watson and the Hovey MMPI scales: do they measure organicity or "functional" psychopathology?

Both the Hovey MMPI Scale of Organicity and the Watson MMPI Sc-O Scale, developed to differentiate schizophrenics from organics, demonstrated substantial association with psychopathology as measured by the MMPI regular clinical and validity scales. These findings occurred with both penitentiary inmates and psychiatric patients. For the Sc-O Scale the correlations with the regular MMPI Scales for the patients tended to be higher than for the prisoners, presumably because of the greater psychopathology present in the former. With the psychiatric patients there was actually a significant inverse relationship between the organicity direction of Sc-O and Hovey Scales, a finding that had been reported in a previous study. The inference from these findings was that MMPI-based organicity scales probably have seriously limited utility, especially in differentiation between organicity and "functional" psychopathology.