Effort-cost decision-making in psychosis and depression: could a similar behavioral deficit arise from disparate psychological and neural mechanisms?

Abstract

Motivational impairment is a common feature of both depression and psychosis; however, the psychological and neural mechanisms that give rise to motivational impairment in these disorders are poorly understood. Recent research has suggested that aberrant effort-cost decision-making (ECDM) may be a potential contributor to motivational impairment in both psychosis and depression. ECDM refers to choices that individuals make regarding the amount of 'work' they are willing to expend to obtain a certain outcome or reward. Recent experimental work has suggested that those with psychosis and depression may be less willing to expend effort to obtain rewards compared with controls, and that this effort deficit is related to motivational impairment in both disorders. In the current review, we aim to summarize the current literature on ECDM in psychosis and depression, providing evidence for transdiagnostic impairment. Next, we discuss evidence for the hypothesis that a seemingly similar behavioral ECDM deficit might arise from disparate psychological and neural mechanisms. Specifically, we argue that effort deficits in psychosis might be largely driven by deficits in cognitive control and the neural correlates of cognitive control processes, while effort deficits in depression might be largely driven by reduced reward responsivity and the associated neural correlates of reward responsivity. Finally, we will provide some discussion regarding future directions, as well as interpretative challenges to consider when examining ECDM transdiagnostically.

Effort–cost computation in a transdiagnostic psychiatric sample: Differences among patients with schizophrenia, bipolar disorder, and major depressive disorder

“…In a study on individuals with SCZ, Huang et al () found that reduced expenditure of physical effort for reward was associated with deactivation of the nucleus accumbens, the posterior cingulate gyrus, and the left medial frontal gyrus. These studies offer only partial support for the distinctions proposed by Culbreth et al () and their sample sizes were small, with no transdiagnostic comparisons.…”

“…In addition, it is unclear whether these deficits result from similar underlying psychological and neural mechanisms. Culbreth, Moran, and Barch () proposed that although psychotic and mood disorders display similar behavioral deficits on effort–cost tasks, these may result from very different mechanisms (i.e., equifinality). They proposed that deficits in effort–cost computation in mood disorders may be a result of reduced reward responsiveness, which stems from blunted activation of the VS (i.e., they do not select high‐effort options because they do not find the incentive offered sufficiently rewarding).…”

The Psychopharmacology of Effort-Related Decision Making: Dopamine, Adenosine, and Insights into the Neurochemistry of Motivation

“…In fact, within the last few years, there has been an explosion of research on effort-related motivational impairments that are seen in disorders such as depression, schizophrenia, and Parkinson's disease. Of course, it needs to be emphasized that psychiatric and neurologic disorders are complex and heterogeneous conditions, and it is possible that the alterations in effort-related decision making that are seen in one disorder may be due to partially overlapping but nevertheless distinct neural mechanisms compared with those seen in other disorders (Culbreth et al, 2018). In contrast, animal studies that focus on the effects of drugs that act on specific receptors or transport proteins, or manipulations such as optogenetics that target specific cell types, are likely to be producing impairments that are relatively specific compared with human pathologies.…”

“…Research on effortrelated motivational functions and dysfunctions involving human participants and animal models is expanding our understanding of the neurochemical basis of motivational symptoms and could ultimately lead to the development of drug treatments for motivational symptoms. Such an approach is validated by human studies showing that alterations in effort-based decision making are associated with depression (Treadway et al, 2012;Yang et al, 2014Yang et al, , 2016Culbreth et al, 2018), schizophrenia (Gold et al, 2013;Culbreth et al, 2018), and Parkinson's disease (Chong et al, 2015).…”

Motivation and Cognitive Control in Depression

“…This cost is weighed against expected benefits in order to choose which actions to pursue (Wallis and Rushworth, 2014). Reduced effort exertion is associated with multiple mental disorders (Culbreth et al, 2018;Salamone et al, 2016). Clinical studies have focused on the exertion of physical effort in order to obtain rewards, demonstrating that anhedonia in depression is related to reduced effort exertion (for an excellent review see: Zald & Treadway, 2017).…”