Mental health, social determinants and One Health in skin neglected tropical diseases (NTDs): A scoping review

Background: Skin NTDs cause mental ill health, primarily through social stigma and discrimination, overburdening services and undermining elimination efforts. A holistic One Health (OH) approach is essential for NTD elimination, but evidence and operational guidance lack. This scoping review documents the current state of integration of mental health and OH-based skin-NTD programmes. It forms part of a series of reviews on the role of OH in skin NTDs, led by the WHO skin NTD working groups. Methodology: We searched four peer-reviewed databases for terms related to skin NTDs, OH, mental health and social determinants of health (SDH). Peer-reviewed articles exploring all four concepts were eligible, with no language/geographical/time constraints. Grey literature, conference abstracts and non-peer-reviewed materials were excluded. Abstract screening and extraction was supported by ASreview and NotebookLM. Outcomes related to mental health, OH/SDH and skin NTDs were analysed and charted, using a descriptive thematic analysis approach. Principal Findings: Twenty-two papers were included; predominantly quantitative studies in Africa, focused on cutaneous leishmaniasis (CL), with few intervention studies. Mental health was typically explored as a downstream effect (primarily stigma and distress), with limited use of validated instruments. Few studies meaningfully embedded OH approaches, including cross-sectoral collaboration and changes were rarely attributed to climate change. A theoretical framework for the multi-directional and intersectional relationship between mental health, SDH and OH is presented. Conclusions/Significance: The underlying mechanisms of mental health remain poorly characterised, with a lack of integrated OH thinking. Exposure to skin NTDs is generally due to lack of agency and choice. Evidence on the role of household economic conditions and climate change in relation to mental health and skin NTDs lacks. Participatory research has a critical role to play in co-designing nuanced OH-informed interventions, but it is critical that we build on identified synergies within existing frameworks, including person-centred care and syndemics. Author summary: Skin neglected tropical diseases (NTDs), including diseases such as leprosy, are associated with mental illness, primarily due to social stigma and discrimination. This burdens the health system and undermines control efforts. The WHO’s NTD Roadmap calls for a holistic One Health (OH) approach, which addresses the health of humans, animals and the environment. However, there is a lack of evidence and guidelines on how to implement such programmes. To address this, the WHO Skin NTD Working Groups launched a series of reviews on the role of OH and skin NTDs. This review focuses on mental health and the social environment and aims to document the current state of integration of mental health and OH-based skin NTD programmes. We conducted a search of peer-reviewed literature covering four dimensions: skin NTDs, OH, mental health and social determinants of health (SDH) (e.g., socioeconomic status). We found limited evidence, with very few articles embedding interventions, measuring mental health outcomes and meaningfully embedding OH. There was also a lack of evidence on household economic conditions and climate change, despite their known importance in shaping mental health and skin NTDs. We present a theoretical framework for the multi-directional and intersectional relationship between mental health, SDH and OH – our hope is that it can support future interventions. The social sciences have a critical role to play in co-designing appropriate OH-informed interventions, but it is vital that we align with existing frameworks like person-centred care.