Addressing gender disparities in the efficacy of psychological interventions for behavioral addictions: protocol for a systematic review and individual patient data meta-analysis of randomized controlled trials

Abstract Background Behavioral addictions (BAs) are increasingly recognized as significant mental health challenges, but evidence on treatment efficacy remains limited. Psychological interventions, particularly cognitive-behavioral therapy (CBT) and its internet-based formats, are considered first-line treatments. However, it remains unclear whether these interventions are equally effective across genders. Addressing this gap is essential for developing gender-sensitive treatment strategies and improving clinical outcomes in individuals with BAs. Methods This systematic review and individual patient data meta-analysis (IPDMA) will evaluate the efficacy of psychological interventions for BAs and examine gender as a potential moderator of intervention outcomes. The primary endpoint is the change in BA symptom severity from baseline to end of treatment, with treatment × gender interaction effects estimated. Eligible randomized controlled trials (RCTs) will be identified through comprehensive database and trial register searches. Study selection, data extraction, and risk-of-bias (RoB) assessment will be conducted independently by two reviewers. RoB will be assessed using the Cochrane RoB 2 tool, and certainty of evidence will be evaluated using the GRADE framework. Principal investigators will be contacted to provide anonymized patient-level data. Data will be synthesized using a two-stage IPDMA with random-effects models, allowing inclusion of trials providing either individual-level data or interaction estimates. Statistical heterogeneity will be quantified using the I 2 statistic, and exploratory analyses will examine intervention characteristics and BA subtypes. Screening and data management will be supported using Covidence, and statistical analyses will be conducted using Python. Expected results We anticipate including a substantial number of RCTs covering different BA subtypes. Based on previous literature, we expect beneficial intervention effects and potential gender-related response variations. Effect sizes may differ between men and women depending on addiction subtype and intervention characteristics. Discussion If gender does not modify treatment effects, the results will support broad applicability; if differences emerge, they will guide tailored, gender-sensitive interventions. This may guide the adaptation of therapeutic approaches to better address the healthcare needs of different gender groups affected by BAs. Systematic review registration PROSPERO CRD420251086582