Performance on the Cognitive Estimation Test in schizophrenia.

The Cognitive Estimation Test (CET) is generally considered to be a measure of executive function, but there is little information with respect to its clinical utility in patients with schizophrenia. In the present investigation, we evaluated the clinical utility of the CET in 42 patients with schizophrenia relative to 42 healthy comparison subjects matched for age, gender, and parental education. Construct validity of the CET was examined though correlation with other tests of executive and nonexecutive cognitive functions. Patients with schizophrenia performed more poorly on the CET compared with the healthy comparison group, which could not be accounted for by greater level of depression in the patient sample. In the schizophrenia group, CET was correlated with measures of executive function but also general intellectual functioning, verbal learning, and auditory attention. CET performance was not associated with depression or overall severity of psychopathology in the patient sample. These findings provide support for the clinical utility of the CET in schizophrenia but indicate that both executive and nonexecutive cognitive functions contribute to performance on the measure. Thus, the integrity of other cognitive processes should be taken into consideration when interpreting the presence of a deficit in cognitive estimation in patients with schizophrenia.