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Objectives: In schizophrenia, a distinction is made between psychosis with developmental and cognitive impairment on the one hand and psychosis without developmental impairment and positive symptoms on the other. In this study, we investigated whether this model can be extended to bipolar disorder by testing the hypothesis that neurocognitive functioning is inversely related to positive psychotic symptoms in bipolar disorder., Methods: Neurocognitive functioning and psychopathology were assessed in (i) 76 patients with bipolar disorder, (ii) 39 of their healthy first-degree relatives, and (iii) 61 healthy controls. Cognitive performance of bipolar patients and their first-degree relatives was investigated, taking into account the possible moderating effect of the level of expression of psychosis in patients and relatives., Results: Bipolar patients showed impaired cognitive performance on multiple cognitive domains, whereas performance of their relatives was comparable to that of controls. A history of psychotic symptoms in patients was suggestive of less likelihood of cognitive alterations in relatives, and the presence of subclinical psychotic symptoms within the group of relatives predicted better cognitive performance., Conclusions: The finding of similar psychosis-cognition associations in bipolar disorder as implied by the two pathways leading to nonaffective psychotic disorders suggests that this model might be extended to the continuum spanning affective and nonaffective psychosis. This is in line with the idea of a partially overlapping vulnerability to bipolar disorder and schizophrenia and provides an explanation for the apparent differences in cognitive alterations in those at risk for the two disorders.

Objective: To investigate the contribution of processing speed in the prediction of various domains of outcome in psychosis., Method: Data were drawn from the UK700 Case Management Trial of 708 patients with chronic psychotic illness. Regression analyses were applied to investigate cross-sectional and longitudinal associations between processing speed at baseline and measures of service use, social outcome and subjective outcome, taking into account current psychopathology and adjusting for baseline values of the outcome measure., Results: Cross-sectionally, processing speed was associated with all three domains of outcome, although only associations in the social and subjective outcome domain remained significant after controlling for psychopathology and the effects differed between and within domains of outcome. Prospectively, only the subjective outcome measure of number of met and unmet needs (CAN) was weakly associated with baseline neurocognitive performance after adjustment for baseline needs. Other associations disappeared after adjustment for the baseline measure of outcome and/or baseline psychopathology., Conclusion: The finding of weak cross-sectional associations in the absence of specific and unconfounded longitudinal associations suggests that processing speed is an independent dimension of disease severity rather than a causal factor impacting on social outcome. Nevertheless, longitudinal change in patient reported needs may be weakly sensitive to baseline cognitive impairment.

Objective: To investigate whether cognitive alterations associated with vulnerability to psychosis, are associated with expression of psychopathology and functional outcome in groups at different levels of risk for psychotic illness., Method: Neurocognition, psychopathology and functional outcome were measured in subjects with variable risk for psychosis: i) 29 patients with psychotic disorder, ii) 46 subjects at familial risk, iii) 41 subjects at psychometric risk and iv) 54 control subjects., Results: Dose-response relationships between cognitive dysfunction and increasing risk for psychosis were found. Cognitive alterations were predicted by negative symptoms in patients and by positive psychotic experiences in the familial risk group. In both at risk groups, cognitive speed was associated with functional outcome., Conclusion: Some cognitive impairments serve as neutral endophenotypic marker across the psychosis continuum. However, other cognitive alterations associated with transmission of psychosis may have a direct impact on the pathway from risk to psychopathology and alterations in functioning.