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Delay Discounting Offers No Predictive Value for MDD Relapse, With Giles Story, PhD
Delay discounting links to residual depression symptoms but does not predict relapse after stopping antidepressant treatment in patients with remitted MDD.
Patients with remitted major depressive disorder (MDD) who show greater impatience for delayed rewards are more likely to report residual depressive symptoms, but that behavioral trait does not predict relapse after stopping antidepressant therapy, according to new longitudinal data.
The findings suggest caution in using delay discounting as a clinical tool for guiding antidepressant discontinuation. Although this behavioral measure reflects known links between depression, impulsivity, and serotonergic function, investigators found it provided minimal predictive value in determining which patients are most likely to relapse after stopping medication.
“The bottom line is probably discounting is not going to be used like a lab test,” Giles W. Story, PhD, from the University College London, told HCPLive.
Rather, clinicians use this study to guide conversations with patients about how depression may be associated with a focus on the present and challenges in planning for the future.
“We know avoidance is a big part of what maintains depression, and through that, people miss out on opportunities for longer-term rewards,” he added.
In a multi-site study led by Doron Elad, PhD, and Story, the study enrolled 97 patients with remitted MDD receiving antidepressant medication and 54 matched healthy controls across sites in Zurich and Berlin. Participants completed validated delay discounting tasks at baseline (MA1) and again after randomization to either antidepressant discontinuation or continuation, with 6 months of follow-up for relapse. Overall, 35% of patients relapsed during follow-up, while 65% remained well.
At baseline, patients with remitted MDD demonstrated significantly steeper delay discounting than controls (Cohen’s d = 0.34), indicating a greater tendency to favor immediate rewards. Delay discounting showed a modest association with depressive symptom severity, even when patients’ symptoms remained below the clinical threshold for relapse. For instance, patients were indifferent between receiving €66 immediately or €75 after a delay, whereas controls were indifferent at approximately €70.
Neither baseline discounting nor changes following antidepressant discontinuation predicted relapse during follow-up. Discontinuation led to only small increases in depressive symptoms, which may have been insufficient to shift discounting behavior.
“The effect that we saw after discontinuation of symptoms was quite small, so people's depressive symptoms did worsen slightly when they stopped medication, but these are people that already have quite low levels of symptoms, and they got just a tiny bit worse,” Story said. “It's probable that discount is probably just not sensitive enough to pick up that small change in symptoms.”
The results also challenge assumptions about behavioral markers as standalone predictors of relapse. Although residual symptoms predict relapse risk overall, they do not reliably predict whether stopping medication increases that risk.
Unexpectedly, higher baseline discounting was associated with greater symptom improvement over time.
“We thought that higher discounts at baseline might be associated with worsening of depression. The fact that we found the opposite strikes a bit of a note of caution,” Story said. “[It] could be a false positive occasionally…it's possible that there's another reason for…why discounting might be increasing depression. On the one hand… maybe that people are not willing to delay gratification, and that's actually part of something that maintains depression…On the other hand, it could be that becoming a bit more impulsive when you're depressed is actually adaptive, and it means that you can get a bit more immediate reward that boosts your mood a bit and carries you through.”
Story has no relevant disclosures.
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