Are psychotic psychopathology and neurocognition orthogonal? A systematic review of their associations.

A systematic review (58 studies, 5,009 individuals) is presented of associations between psychopathological dimensions of psychosis and measures of neurocognitive impairment in subjects with a lifetime history of nonaffective psychosis. Results showed that negative and disorganized dimensions were significantly but modestly associated with cognitive deficits (correlations from -.29 to -.12). In contrast, positive and depressive dimensions of psychopathology were not associated with neurocognitive measures. The patterns of association for the 4 psychosis dimensions were stable across neurocognitive domains and were independent of age, gender, and chronicity of illness. In addition, significantly higher correlations were found for the negative dimension in relation to verbal fluency (p = .005) and for the disorganized dimension in relation to reasoning and problem solving (p = .004) and to attention/vigilance (p = .03). Psychotic psychopathology and neurocognition are not entirely orthogonal, as heterogeneity in nonaffective psychosis is weakly but meaningfully associated with measures of neurocognition. This association suggests that differential latent cerebral mechanisms underlie the cluster of disorganized and negative symptoms versus that of positive and affective symptoms.