Delay Discounting in Established and Proposed Behavioral Addictions: A Systematic Review and Meta-Analysis

Abstract

Steep delay discounting, or a greater preference for smaller-immediate rewards over larger-delayed rewards, is a common phenomenon across a range of substance use and psychiatric disorders. Non-substance behavioral addictions (e.g., gambling disorder, internet gaming disorder, food addiction) are of increasing interest in delay discounting research. Individual studies have reported steeper discounting in people exhibiting various behavioral addictions compared to controls or significant correlations between discounting and behavioral addiction scales; however, not all studies have found significant effects. To synthesize the published research in this area and identify priorities for future research, we conducted a pre-registered systematic review and meta-analysis (following PRISMA guidelines) of delay discounting studies across a range of behavioral addiction categories. The final sample included 78 studies, yielding 87 effect sizes for the meta-analysis. For studies with categorical designs, we found statistically significant, medium-to-large effect sizes for gambling disorder (Cohen’s d = 0.82) and IGD (d = 0.89), although the IGD effect size was disproportionately influenced by a single study (adjusted d = 0.53 after removal). Categorical internet/smartphone studies were non-significant (d = 0.16, p = 0.06). Aggregate correlations in dimensional studies were statistically significant, but generally small magnitude for gambling (r = 0.22), internet/smartphone (r = 0.13) and food addiction (r = 0.12). Heterogeneity statistics suggested substantial variability across studies, and publication bias indices indicated moderate impact of unpublished or small sample studies. These findings generally suggest that some behavioral addictions are associated with steeper discounting, with the most robust evidence for gambling disorder. Importantly, this review also highlighted several categories with notably smaller effect sizes or categories with too few studies to be included (e.g., compulsive buying, exercise addiction). Further research on delay discounting in behavioral addictions is warranted, particularly for categories with relatively few studies.

A Model Guided Approach to Evoke Homogeneous Behavior During Temporal Reward and Loss Discounting

“…In line with this argument, individuals with impulsive disorders and addiction show steeper discounting of future rewards such as monetary gains [for overviews see (12)(13)(14)(15)]. Moreover, steeper discounting does not only differentiate between addiction disorders and healthy individuals, but it also predicts entry into drug use as well as therapy outcome (16,17), and has accordingly been described as a behavioral biomarker of addiction and its treatment (18).…”

Examination of Individual Differences in Susceptibility to Food Addiction using Alcohol and Addiction Research Domain Criteria (AARDoC): Recent Findings and Directions for the Future

“…These studies have generally suggested a small relationship between delay discounting and FA [22,[52][53][54][55]. In addition, a recent meta-analysis suggested aggregate correlations between FA and steeper discounting were significant but small in magnitude (r = 0.12) [56]. This is in contrast to a meta-analysis that concluded a robust association between delayed reward discounting across many addictive substances [46].…”

Delay Discounting in Gambling Disorder: Implications in Treatment Outcome

“…Several studies have found higher discount rates in patients with GD than healthy controls [ 15 , 19 , 20 , 21 , 22 , 23 ]. Moreover, there is evidence of an association between the severity of GD symptoms and high discount rates [ 22 , 24 ].…”