Background Mental disorders – such as depression – are among the leading causes of ill health affecting an estimated one billion people worldwide. With these numbers growing by nearly 50% between 1990–2019, population-level intervention is urgently needed to help improve public mental health (PMH), reduce mental health inequalities, and ease demand on overstretched health services.

Adopting a population-level approach to PMH includes addressing social determinants such as housing. However, PMH initiatives have largely overlooked the role of commercial actors, and their health harming products and activities. Tackling such commercial determinants is important for improving physical health, and could equally represent an overlooked means to foster good PMH.

Methods This review sought i) to map the evidence base regarding the impact on mental health of population-level interventions addressing the commercial determinants of health (CDoH) and ii) identify knowledge gaps. The project focused on six industries (tobacco, alcohol, ultra-processed foods, gambling, social media and fossil fuels) with more generic commercial activities also included in the search strategy. Medline, Embase, Psychinfo, Scopus and the Cochrane Library databases were searched. The references of identified umbrella reviews were also screened.

Eligible papers were systematic reviews containing empirical data, published after 1/1/2012 in English. Population-level interventions evaluated in high and/or low-income settings were included. Mental health outcomes were anxiety, depression, self-harm and suicide whilst surrogate outcomes included product consumption.

In addition to methodological quality appraisal, assessments were undertaken to rate industry involvement in the included reviews.

A narrative synthesis was undertaken to map the identified evidence. Analysis included considering commonalities and points of divergence between industries.

Results The search identified 34,365 de-duplicated results with 548 papers selected for full-text review. The final set of papers for inclusion is being currently finalised (Feb 2023).

Preliminary findings suggest that the mental health impacts of interventions addressing the CDoH are rarely evaluated. For example, of the 31 included reviews of alcohol interventions, only seven reported mental health outcomes. They described a reduction in suicide rates or mental health hospital admissions following interventions to lessen alcohol availability. Despite known biological pathways linking alcohol consumption and anxiety or depression, no reviews measured these outcomes.

Conclusion This umbrella review is the first to map the evidence on the mental health impacts of tackling the CDoH. Its findings will be relevant to PMH policymaking and research communities. It also contributes to evidence synthesis methods within the rapidly-growing field of CDoH research.