Awareness of cognitive impairment in schizophrenia and its relationship to insight into illness

Patients with schizophrenia have been found to show unawareness of cognitive impairment. However, its frequency and its relationship to lack of insight into illness are uncertain.

Forty-two patients with chronic schizophrenia were given tests of executive function and memory. Awareness of cognitive impairment was measured by means of discrepancy scores--differences between patient and psychologist ratings of memory and frontal/executive failures in daily life. Insight into illness was assessed using the Scale to Assess Unawareness of Mental Disorder (SUMD).

A majority of the patients were found to underestimate their cognitive impairment; however, some overestimated it. Unawareness of cognitive impairment and lack of clinical insight loaded on different factors in a factor analysis, but these two factors were themselves correlated.

The findings suggest that both unawareness and overestimation of cognitive impairment characterise patients with schizophrenia, although the former is more common. Awareness of cognitive impairment occurs independently of insight into illness at the clinical level, although the two phenomena may be linked at a deeper level.