Risk of stillbirth among pregnant women with anaemia in India: secondary analysis of multiple cohorts from the ICMR-SPIC consortium.

Major depressive disorder (MDD) profoundly affects various aspects of individuals’ lives, including motivation, decision making, and willingness to exert effort. Diagnostic criteria for MDD include fatigue as a core symptom (), which can affect these behaviors, disrupting the ability to engage in tasks that require cognitive effort. Although there has been a great deal of work examining how MDD influences decisions to exert effort, and fatigue is a well-established symptom, there is limited understanding of how MDD-induced fatigue affects decision making and motivated performance. In this study, we examine how individuals with MDD trade cognitive effort for rewards and how fatigue and depressive symptoms shape this decision-making process. Effort-based decision-making has been proposed as a behavioral approach for understanding motivation. In this framework, the willingness to exert effort is influenced by the subjective value of the rewards associated with a particular outcome, as well as the trade-off between the reward and the effort required to obtain it. Effort-based decision-making studies have been applied in the context of physical (, , , , , , , , ) and cognitive (,, , ) effort in healthy individuals, revealing that the willingness to undertake effort increases as the levels of prospective effort-contingent reward rise, and that the subjective value of effort increases through repeated fatigue-induced exertion. Recently, several studies have explored effort-based decision-making in individuals with MDD, focusing on both cognitive and physical effort. Although many studies have reported that individuals with MDD are less willing to exert cognitive (, , , , ) and physical (, , , , , , , ) effort compared with healthy individuals, findings across studies have been somewhat inconsistent, with some reporting reductions in effort expenditure in individuals with MDD, whereas others have observed relatively preserved effort-based choice behavior or effects that vary across symptom dimensions and diagnostic categories (,, , ). One potential explanation for these inconsistencies is that prior work has largely focused on diagnostic group differences without explicitly considering variability in fatigue-related symptoms, even though fatigue is a hallmark feature of MDD that may substantially influence willingness to engage in effortful behavior. Consistent with this idea, studies of effort-based decision-making have shown that feelings of fatigue significantly influence choice behavior (,,,,,,), and individuals with depression tend to perceive activities as more effortful than healthy controls (,). However, there has been limited investigation into how fatigue symptoms specifically contribute to effort-based decision-making in individuals with MDD. Therefore, this study was designed to examine whether fatigue-related symptoms contribute to variability in cognitive effort-based decision-making in MDD.