Intimate partner violence (IPV) and unhealthy alcohol use are common yet often unaddressed public health problems in low- and middle-income countries. In a randomized trial, we found that the common elements treatment approach (CETA), a multi-problem, flexible, transdiagnostic intervention, was effective in reducing IPV and unhealthy alcohol use among couples in Zambia at a 12-month post-baseline assessment. In this follow-up study, we investigated whether treatment effects were sustained among CETA participants at 24-months post-baseline.

Participants were heterosexual couples in Zambia in which the woman reported IPV perpetrated by the male partner and in which the male had hazardous alcohol use. Couples were randomized to CETA or treatment as usual plus safety checks. Measures were the Severity of Violence Against Women Scale (SVAWS) and the Alcohol Use Disorders Identification Test (AUDIT). The trial was stopped early upon recommendation by the trial's DSMB due to CETA's effectiveness following the 12-month assessment. Control participants exited the study and were offered CETA. This brief report presents data from an additional follow-up assessment conducted among original CETA participants at a 24-month visit.

There were no meaningful changes in SVAWS or AUDIT scores between 12- and 24-months. The within-group treatment effect for SVAWS from baseline to 24-months was d = 1.37 (p < 0.0001) and AUDIT was d = 0.85 (p < 0.0001).

The lack of change in levels of IPV and unhealthy alcohol use between the 12- and 24-month post-baseline timepoints suggests that treatment gains were sustained among participants who received CETA for at least two years from intervention commencement.

A four- to seven-fold increase in the prevalence of current mood, anxiety, substance use and any mental disorders in Indigenous adults compared with non-Indigenous Australians has been reported. A lifetime prevalence of major depressive disorder was 23.9%. High rates of comorbid mental disorders indicated a transdiagnostic approach to treatment might be most appropriate. The effectiveness of psychological treatment for Indigenous Australians and adjunct Indigenous spiritual and cultural healing has not previously been evaluated in controlled clinical trials.

This project aims to develop, deliver and evaluate the effectiveness of an Indigenous model of mental healthcare (IMMHC). Trial registration: ANZCTR Registration Number: ACTRN12618001746224 and World Health Organization Universal Trial Number: U1111-1222-5849.

The IMMHC will be based on transdiagnostic cognitive–behaviour therapy co-designed with the Indigenous community to ensure it is socially and culturally appropriate for Indigenous Australians. The IMMHC will be evaluated in a randomised controlled trial with 110 Indigenous adults diagnosed with a current diagnosis of depression. The primary outcome will be the severity of depression symptoms as determined by changes in Beck Depression Inventory-II score at 6 months post-intervention. Secondary outcomes include anxiety, substance use disorder and quality of life. Outcomes will be assessed at baseline, 6 months post-intervention and 12 months post-intervention.

The study design adheres to the Consolidated Standards of Reporting Trials (CONSORT) statement recommendations and CONSORT extensions for pilot trials. We followed the Standard Protocol Items for Randomised Trials statement recommendations in writing the trial protocol.

This study will likely benefit participants, as well as collaborating Aboriginal Medical Services and health organisations. The transdiagnostic IMMHC has the potential to have a substantial impact on health services delivery in the Indigenous health sector.