World Health Day highlights the importance of protecting and promoting health worldwide. This year’s theme, “Together for health. Stand with science,” set by the World Health Organization, emphasises the importance of working together, strengthening trust in science, and ensuring that knowledge is translated into action through collaboration.

Substance use continues to affect individuals, families, and communities across the world, making it a persistent public health challenge. Addressing it requires sustained commitment, along with coordinated approaches that draw on research to understand risk and protective factors, and translate that knowledge into effective policies and programmes.

At the centre of this is the right to health, which includes access to prevention, treatment, and recovery support. Yet in practice, many people still lack access to these services. Prevention is often underprioritised, while treatment and long-term recovery support remain limited in many settings.

Strengthening prevention is therefore essential. Prevention efforts, particularly those focused on children and young people, support healthy development and help prevent substance use when grounded in scientific knowledge. Over the past decades, prevention science has advanced significantly, and there is growing evidence on what works and what does not. This provides a strong foundation for governments and organisations to implement effective approaches that promote health and wellbeing. At the same time, sustained commitment is needed. Continued investment, alongside monitoring and evaluation of interventions, is essential to ensure that efforts are effective in practice. While many initiatives are driven by strong intentions, not all are rooted in evidence. Strengthening the use of science in prevention is therefore key to achieving lasting impact. Prevention efforts also contribute to lowering long-term costs across health, social, and justice systems, making them both impactful and cost-effective.

Access to care remains a critical gap. People affected by substance use often face significant barriers when seeking support, including stigma, limited availability of services, and a lack of sustained recovery support. As recognised in the International Standards for the Treatment of Drug Use Disorders, developed jointly by the United Nations Office on Drugs and Crime and the World Health Organization, stigma and discrimination are major barriers to accessing treatment. These barriers can discourage people from seeking help and limit access to care, with wider consequences for families and communities. Addressing this requires not only expanding services, but applying this knowledge to ensure that support is accessible, responsive, and appropriate over time.

These challenges highlight the need for stronger coordination. Health systems, education, social services, and communities all form part of the response, and closer cooperation between them is essential. Bringing together scientific evidence, professional practice, and lived experience is key not only to understanding complex health challenges, but to translating knowledge into effective action. Strengthening trust in science and fostering collaboration across sectors will be essential to building more resilient and sustainable responses.

On this World Health Day, we recognise and thank our members, partners, and civil society organisations worldwide. Your continued work in prevention, treatment, and recovery contributes directly to stronger communities and improved health outcomes.

Standing with science means strengthening prevention, improving access to treatment and recovery, and ensuring that knowledge is translated into action through coordinated and evidence-informed responses. Through sustained collaboration, it is possible to build healthier and more resilient societies.