Neurocognition, Cognitive Remediation and Functional Outcome in Schizophrenia Spectrum Disorders

Abstract

Employment rates in schizophrenia are consistently low. Considerable research has identified both societal/external barriers and internal, illness related barriers to employment. Neurocognitive impairments are a hallmark of schizophrenia spectrum disorders, contributing to impaired real-world functioning in general and significant occupational disability in particular. The consequences of these deficits are profound and largely consistent over time. The main aim of the current thesis was to further investigate neurocognition in participants with broad schizophrenia spectrum disorders as measured with the MATRICS Consensus Cognitive Battery (MCCB). Findings from Paper I revealed significant impairments on all neurocognitive domains, supporting findings from similar studies. Neurocognitive performance differentiated between academic levels and previous work history and overlapped with social functioning. Further we sought to investigate whether neurocognitive test performance was associated with different aspects of occupational outcome; i.e. workplace assessments. Paper II found significant associations between all MCCB domains except Verbal Learning and vocational cognitive functioning at the beginning of vocational rehabilitation. Processing Speed and Attention predicted work behavior and neurocognitive performance was also associated with task complexity and type of work. Participants performing low complexity jobs performed worse on all neurocognitive domains with a similar pattern emerging for participants in sheltered work, performing poorer on all neurocognitive tests than participants in competitive work. In Paper III, we examined the effects of the Job Management Program (JUMP); i.e. cognitive remediation (CR) in combination with vocational rehabilitation on neurocognition and occupational outcomes compared to cognitive behavioral therapy techniques (CBT) augmented vocational rehabilitation (VR). We found neurocognition to improve after both CBT- and CR-augmented vocational rehabilitation, with the greatest improvement in the CR group. There was also an increase in number of participants working and the amount of time they were working throughout the project period. The positive change in Working Memory and the Neurocognitive Composite Score predicted number of hours worked in the CR group. These findings indicate neurocognitive dysfunctions in participants with schizophrenia spectrum disorders and that these dysfunctions are relevant for occupational functioning. Particularly, Processing Speed and Attention predicted different aspects of work behavior. This ties in with findings from similar studies, showing Processing Speed to be one of the strongest correlates to functional outcome and Attention to be of particular relevance at the beginning of vocational rehabilitation. Our findings further indicate that implementing a combination of vocational rehabilitation, cognitive behavioral techniques or cognitive remediation may help participants attain and maintain work. Employment numbers increased significantly throughout the intervention period and remained high at follow-up. Positive neurocognitive change between baseline and post treatment in the Working Memory domain and the Neurocognitive Composite Score predicted number of hours worked 2 years after inclusion in the study. Our findings underline the need for future studies that investigate which subgroups profit more (or less) from cognitive remediation and vocational rehabilitation. Stratifying on degree of impairment may thus shed further light on this matter. Also, assessing learning potential and motivation as possible mediators between neurocognition and real-world functioning may be of importance. Lastly, additive effects of strategy learning, both in general and task specific should be addressed as it may enhance gains on neurocognitive performance and in turn, functional outcome.