Clarifying the direction of impact of negative symptoms and neurocognition on prospective work functioning in psychosis: A 20-year longitudinal study

Abstract

Both neurocognition and negative symptoms have demonstrated strong links to functional outcomes, such as work functioning, among those with severe mental illness (SMI). Prior models have suggested that reduced neurocognition 1) precedes or predicts greater negative symptoms and 2) indirectly influences functional outcomes via its impact on negative symptoms. The current study sought to also test a divergent model: whether greater negative symptoms predict reduced neurocognition and indirectly influence work functioning through their impact on neurocognition. Both models were tested using cross-sectional and prospective data spanning 20-years in a sample of 277 people with a SMI with psychotic features. Results showed that both models were supported in cross-sectional analyses. However, in prospective models predicting work functioning, only the models examining the indirect influence of negative symptoms on work functioning (7.5 to up to 20-years later) through neurocognition demonstrated significant mediation (i.e., a significant indirect effect); further, higher negative symptoms significantly predicted lower prospective neurocognition, while lower neurocognition did not significantly predict greater prospective negative symptoms. Although cross-sectional data were consistent with prior models, our prospective models offered greater support for a putative causal pathway running from negative symptoms to neurocognition-rather than the reverse-to work functioning. Findings have implications for mechanisms contributing to longitudinal work functioning and suggest that targeting negative symptoms prior to neurocognition could be more beneficial for long-term work outcomes.

Keywords: Negative symptoms; Neurocognition; Psychosis; Severe mental illness; Vocational rehabilitation; Work.

Figure 1.

Hypothesized model testing mediating effects of negative symptoms in associations between neurocognition and work functioning. For clarity, covariances and error terms are not depicted.

Figure 2.

Hypothesized model testing mediating effects of neurocognition in association between negative symptoms and work functioning. For clarity, covariances and error terms are not depicted.