Is unawareness of psychotic disorder a neurocognitive or psychological defensiveness problem?

We examined whether deficits in attention and perceptual encoding as well as psychological defensiveness were associated with impaired awareness of disorder in schizophrenia. The Scale for Unawareness of Mental Disorder (SUMD) was administered to 52 outpatients with a recent onset of schizophrenia approximately 1-2 months following hospital discharge. Two versions of the Continuous Performance Test (CPT) were used to measure attentional impairment--the Degraded Stimulus CPT (DS-CPT) and a memory-load version (3-7 CPT). Three scales from the Minnesota Multiphasic Personality Inventory were used as indicators of psychological defensiveness: Scales L (Lie), K (Correction), and R (Repression). The Classification and Regression Tree (CART) program, a nonparametric statistical method, was used to identify relationships among multiple predictor variables and to provide optimal splitting scores for each predictor variable. Different combinations of poor target discrimination (d') on the 3-7 CPT and a cautious response style on the DS-CPT were associated with the three levels of overall unawareness of having a mental disorder. For nonpsychotic patients, better target discrimination (d') on the 3-7 CPT tended to be associated with better awareness of having a mental disorder. In contrast, unawareness among the patients who were psychotic at the time of the SUMD administration was not discriminated by attentional measures, but was associated with a combination of two measures of psychological defensiveness from the MMPI reflecting guardedness, psychological suppression, attempting to present oneself in a socially desirable light, and social acquiescence. Generally similar associations were found for two other dimensions of poor insight: unawareness of the beneficial effects of antipsychotic medication, and inability to attribute unusual thoughts and hallucinatory experiences to a mental disorder.