Relationship of scales of schizophrenia proneness and premorbid adjustment to thinking deficits in schizophrenia

Scales of premorbid adjustment, which generally rely very heavily upon assessment of premorbid social functioning, long have been known to predict some forms of thinking disorder in schizophrenia. Several scales theorized to detect schizophrenia proneness were compared to the Phillips Scale of Premorbid Adjustment to determine whether the characteristics measured by the proneness scales might underlie the predictive power of premorbid social functioning. In a sample of 48 schizophrenics, only the Phillips Scale predicted performance on the Gorham's Proverb Test. These data give no evidence that anhedonia, ambivalence, or perceptual aberration underlie defective schizophrenic social functioning. Cautions and other uses for the schizophrenia proneness scales are discussed.