5 - (OP5) Enjoyment-motivation Coupling in Depression: A Dynamic Structural Equation Modeling Approach

Rewards strongly shape behavior, decision-making, and learning. Neuroscientific evidence has demonstrated that aspects of reward processing correspond with distinct neurobiological pathways. Depression is characterized by anhedonia, or low positive affect, as well as deficits in reward learning, responsiveness, and valuation. Current treatments for depression presume that facets of reward are inherently interconnected. However, it is not well-understood how specific sub-constructs of reward processing relate to one another over time, particularly in the context of elevated depression and anhedonia. Here, we investigated reciprocal relationships between motivation and enjoyment.

Participants (N = 330; 68% Female) with moderate-severe depression and low, moderate, and high levels of anhedonia were recruited. Depression severity was assessed by the Patient Health Questionnaire-14. Across 3 months, participants completed 3 waves of ecological momentary assessment (EMA; 5 times per day over 8 days). Enjoyment (1-7 scale) and motivation (1-5 scale) were each measured by a single item. Using dynamic structural equation models in Mplus we investigated cross-lagged and autoregressive effects between enjoyment and motivation in each wave. We further examined the impact of depression by evaluating the correlation between symptoms at the start of the EMA wave and random effects in the primary models. Additionally, we conducted exploratory analyses to better understand the influence of depression severity. We evaluated additional models in subsets of participants with the top (N = 80) and bottom (N = 88) quartiles of depression scores in wave 1. Results were considered significant if 95% credible intervals did not contain zero. All models converged adequately based on Potential Scale Reduction and visual inspection of trace and autocorrelation plots.

Results across primary models revealed significant within-person cross-lagged effects, such that prior motivation positively predicted later enjoyment, and vice versa. We also found significant within-person autoregressive effects, or inertia, signifying that prior motivation and enjoyment were predictive of later motivation and enjoyment, respectively. In correlations among between-person effects, depressive symptoms were negatively related to both motivation and enjoyment. Further, enjoyment and motivation were reciprocally related in those with the bottom 25% of depressive symptoms, but not the top 25%.

The present findings suggest motivation and enjoyment are reciprocally related in individuals with depression. That is, when individuals experience greater enjoyment, they are more likely to report greater motivation later, and vice versa. However, we also found that the enjoyment-motivation coupling may be disrupted in those with the greatest depression symptom severity. As such, a weakened relationship between enjoyment and motivation may signal broader deficits in the reward system. Our study is among the first to detect a reciprocal relationship between motivation and enjoyment and to clarify how this relationship may be impacted by depression severity, providing novel insights into daily life reward dynamics in individuals with depression.