Moderator effects in a randomized controlled trial of the Common Elements Treatment Approach (CETA) for intimate partner violence and hazardous alcohol use in Zambia

Background: Intimate partner violence (IPV) and hazardous alcohol use are prevalent and co-occurring problems in low- and middle-income countries (LMICs). While limited evidence suggests that cognitive behavioral therapy (CBT) interventions can help address these problems, few randomized trials in LMICs have investigated moderators of treatment effectiveness. This study explores moderating factors impacting responsiveness to a CBTbased intervention for IPV and hazardous alcohol use among couples in Zambia. Methods: Data were obtained from a completed randomized trial of a CBT-based intervention, the Common Elements Treatment Approach (CETA), among 248 couples in Lusaka. Female experiences of IPV and male alcohol use were measured at baseline and 12 months post-baseline. Mixed effects regression models were used to evaluate each moderator: age, educational attainment, employment status, marital status, physical disability, HIV status, trauma exposure, depression, post-traumatic stress disorder, alcohol use disorder, and substance use. Results: Treatment effectiveness for male alcohol use was moderated by female substance use, with greater reductions among men whose partners reported using non-alcohol substances (e.g., cannabis) (p < 0.01). Other marginally significant moderators (p < 0.15) of change in male alcohol use included female education and male depression, substance use, and moderate-to-severe alcohol use at baseline. Female HIV status and depression were marginally significant moderators of change in IPV. Conclusions: This study suggests that CETA may be especially effective for highly symptomatic individuals with comorbid mental and behavioral health problems, a promising finding given that such comorbidity is widespread in LMICs. Psychotherapeutic treatments that can flexibly and simultaneously address co-occurring problems are needed.