New review finds the benefits of a widely-used treatment for gambling problems may be overstated

Peer reviewed: Yes
Method of research: Meta-analysis
Subject of study: People 

A new meta-analysis (an analysis of past research) published by the scientific journal Addiction presents important findings that shed light on the effectiveness of psychological treatments for gambling problems. The analysis provides both positive and negative insights, including uncovering potential overstatements of the benefits associated with using cognitive-behavioural techniques (CBTs). Significantly more funds are essential to increase the rigor of studies and to improve understanding of treatment impact among individuals experiencing gambling problems.  

The analysis pooled the results of 29 randomised controlled trials of CBTs on reducing gambling problems and gambling behaviour, representing almost 4,000 participants. The analysis revealed that participants receiving CBTs had larger reductions in the severity of gambling problems, the number of times gambled, and the amount of money gambled than minimal or no treatment at posttreatment. However, the analysis revealed some concerning factors that may have led to an overestimation of the treatment’s impact. There was also no evidence that reductions in outcomes endured in the months and years after participants terminated CBTs.  

The meta-analysis found evidence of publication bias, which occurs when the outcome of a research study affects the decision to publish it. Studies with small sample sizes and large treatment effects overpopulate the literature, and few studies have been conducted that comprise large sample sizes of individuals completing CBTs. Of course, such studies may not exist, but if they do exist, they have not been published – perhaps because the results are not as dramatic – and their data are thus not available to counterbalance the effects of the studies that have been published.  

Across the 29 trials, only three studies (10%) had implemented designs to minimize risk of bias, which is the likelihood that the design or conduct of a study will give a misleading result. Most studies had a high attrition rate, meaning lots of participants dropped out of the study partway through, so that posttreatment results were based on incomplete data, perhaps concentrated among people for whom the treatment worked well.  

Less than half of the 29 studies (48%) reported results beyond the posttreatment assessment.  That means the estimate of how well participants sustained their improved gambling outcomes beyond treatment was based on a comparatively small amount of data.  

Lead author Dr. Rory Pfund of the University of Memphis suggests that some of the shortcomings of the 29 gambling studies can be blamed on the overall lack of funding for gambling research across several countries. For example, in the US: “No US federal agency funds programs to address gambling disorder. Total state funds for gambling treatment centers and program evaluations were limited to $14 million in 2016. That amount is about 4,000 times smaller than the $550 million of federal funds available for alcohol research and about 13,000 times smaller than the $1.8 billion available for drug research in 2022.”  

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For editors:

This paper is free to read for one month after publication from the Wiley Online Library: or by contacting Jean O’Reilly, Editorial Manager, Addiction,

To speak with co-author Dr Rory Pfund, please contact him at the University of Memphis by email ( or telephone (+1 901 678 8720).

Full citation for article: Pfund RA, Forman DP, King SA, Zech JM, Ginley MK, Peter SC, McAfee NW, and Whelan JP. Effect of Cognitive-Behavioral Techniques for Problem Gambling and Gambling Disorder:  A Systematic Review and Meta-Analysis. Addiction. 2023. DOI: 10.1111/add.16221.

Funding: This work was supported by the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health award numbers L30AA029551 and T32AA018108. This work was also supported by a grant from Tennessee Department of Mental Health and Substance Abuse Services.  

Declaration of interests:  None.