Research That Matters (January 17 - 20, 2008)

Background and Purpose: Despite the long-standing recognition of motivational difficulties experienced by persons with schizophrenia, there is little understanding of the nature and mechanisms of intrinsic motivation in schizophrenia and how it relates to neurocognition and functional outcome. This study aimed to: (i) examine the strength of the relationships among neurocognition, intrinsic motivation, and psychosocial functioning in schizophrenia; (ii) explore whether intrinsic motivation mediated the relationship between neurocognition and psychosocial functioning, and (iii) to examine if neurocognition moderated the relationship between intrinsic motivation and psychosocial functioning outcomes. Methods: The sample included 120 individuals diagnosed with schizophrenia involved in community-based psychosocial rehabilitation programs. Subjects completed baseline measures of neurocognition, motivation, psychosocial functioning, and symptoms. Five measures used to assess neurocognition included verbal fluency, immediate memory, secondary memory, sustained attention, and mental flexibility. Intrinsic motivation was measured by the sum of three items from the intrapsychic deficits sub-scale of the Quality of Life Scale: purpose, drive, and curiosity. The psychosocial measure assessed work, independent living, and social functioning. Psychosocial functioning data were gathered within two weeks of neurocognitive testing. Trained research interviewers who conducted the semi-structured psychosocial interviews were blind to the neuropsychological results. Structural equation modeling with latent variables was used to test the mediator and moderator models. Results: There were significant bivariate correlations between all three variables (Pearson r ranged from .28 - .5). Controlling for symptoms, the mediator model demonstrated very good fit to the data, (χ2 (48, N = 120) =58.19, p > .10; CFI = .97; RMSEA = .04, CI: .00, .08). The direct paths from neurocognition to motivation, and from motivation to psychosocial functioning were statistically significant. While the direct path from neurocognition to psychosocial functioning was no longer statistically significant, the indirect path coefficient from neurocognition to psychosocial functioning through motivation was .08 (.03), and was statistically significant (p < .05). The results suggest that intrinsic motivation is a process through which neurocognition influences psychosocial functioning outcomes. There was no support for the moderator model. Conclusions and Implications: Outcomes from this study indicate that intrinsic motivation is an important concept for understanding the mechanisms of how neurocognition influences functional outcome in schizophrenia. The findings also suggest that developing interventions to improve intrinsic motivation could contribute to better functional outcomes and quality of care for persons with schizophrenia. Theory-driven investigations identifying mediators and moderators have the potential to help test and develop theory, and to identify active ingredients or process variables in interventions so that they can be adapted and optimized to increase efficacy and cost-effectiveness. Source of Funding: NIMH, F-31 (Grant #: 1F31MH078366), Eri Nakagami, (Ph.D. Candidate), John Brekke, Ph.D. (Sponsor)