Antecedents and Functional Outcomes of Motivation to Expend Physical and Cognitive Effort in Early Psychosis
Individuals experiencing chronic psychotic illness face immense functional burden, signaling the public health need to understand and address barriers to recovery for early psychosis patients. By the first episode of psychosis, individuals exhibit more difficulties with making decisions to allocate effort for physical and cognitive tasks than their healthy peers. Research has yet to elucidate how these effort allocation difficulties interact with illness factors and environment systems to bring about functional impairments in the real-world. This dissertation administered a biobehavioral paradigm examining decisions to expend physical effort for reward and a novel, structurally parallel paradigm on cognitive effort to an early psychosis outpatient sample. The overall research objective was to understand the etiological mechanisms of dysfunctional effort allocation in early psychosis, from antecedent predictors to its concurrent and 3-month prospective functional consequences. The chapters herein describe different analyses performed on one sample. Chapter 2 distinguished the degree to which parameters of a task’s reinforcement context, cognitive control, and negative symptom dimensions, predicted physical versus cognitive effort. Probability of pay-out advertised by the task disproportionately drove decisions to expend cognitive effort, whereas expected value (probability and reward) and cognitive control, in combination with mild levels of expressive negative symptoms, positively predicted physical effort-based decision-making. Chapter 3 tested an adapted schizophrenia model of functioning in early psychosis, whereby impaired cognition is posited to predict poor life functioning via effort expenditure motivation. While cognition shared a very small relationship with functional outcomes, the study findings highlighted that cognitive, but not physical, effort expenditure and modulation have implications for functioning. Chapter 4 explored a novel mechanism of functional status. The study found that more severe motivation and pleasure negative symptoms partially accounted for the indirect effect of reduced cognitive effort on poor functional status. Greater expressive negative symptom severity was the key mediator of the physical effort and functional status relationship. Findings collectively inform a working model of functioning in early psychosis where impaired cognitive control, dysfunctional expenditure of different types of effort, and severe negative symptom dimensions, in this order, may translate to poor life functioning.
Psychosis, Motivation, Effort, Functioning, Negative symptoms, Cognitive control
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