Factors influencing treatment outcomes in a randomised clinical trial for gambling disorder

Abstract

Background: Sociodemographic background factors, gambling game type, depressive symptoms and comorbid substance misuse have been associated with gambling disorder, but the effects of these factors on treatment outcomes remains unclear. The aim of this study was to examine the background factors associated with treatment outcomes in a clinical trial for gambling disorder. Methods: This was a secondary analysis of a single-centre 12-week randomised placebo-controlled clinical trial investigating the effects of as-needed intranasal naloxone in the treatment of gambling disorder. Data was analysed with linear mixed models, with analyses both including and excluding treatment effect. Results: Sociodemographic factors or game types were not associated with treatment outcomes. Adherence to the investigative medicinal product (IMP) dosing regimen was associated with greater reduction in gambling urge and severity, and greater increase in gambling self-efficacy. Higher readiness to change gambling behaviour was associated with greater gambling self-efficacy. Higher scores for depressive symptoms at baseline were associated with a greater increase in quality of life after the treatment. When treatment allocation was incorporated as a nuisance variable, most results that were previously identified as statistically significant were consequently nullified. Conclusion: Authors hypothesize that recognizing gambling urges and acting in response to them is the underlying factor behind the positive effects of medication adherence in this trial. More rigorous monitoring of IMP use is recommended for future trials with as-needed formulations. Trial registration: EudraCT number: 2017-001946-93 and ClinicalTriels.gov: NCT0343018).