Neuropsychological deficits in psychotic versus nonpsychotic major depression and no mental illness

At least three studies have indicated that patients with psychotic major depression studied under non-drug-free conditions differ from patients with nonpsychotic major depression and healthy comparison subjects on several measures of neuropsychological performance. The current study explored specific impairments in cognitive function in subjects with psychotic major depression, subjects with nonpsychotic major depression, and healthy comparison subjects studied under drug-free conditions.

A battery of neuropsychological tests was administered to 11 patients with psychotic major depression, 32 patients with nonpsychotic major depression, and 23 normal comparison subjects under drug-free conditions. The three groups did not differ statistically in age, sex, or level of education. To ensure that participants had minimal levels of severity and endogenicity, all patients were required to have a score of at least 20 on the 21-item Hamilton Depression Rating Scale and a score of at least 7 on the Core Endogenomorphic Scale, which uses eight items from the Hamilton depression scale.

Patients with psychotic major depression demonstrated significantly greater impairment than patients with nonpsychotic major depression and/or comparison subjects in attention and response inhibition (as measured by the Stroop color-word subscale score) as well as in verbal declarative memory (as measured by the Paragraph Recall Test).

These data indicate that patients with psychotic major depression demonstrate impairment in functions thought to be mediated by the frontal cortex and mediotemporal lobes.