Before evaluating an NPI, it is essential to describe it. Sometimes, health practices may involve a combination of diagnostic methods and treatments, as seen in osteopathy. An NPI is not intended to identify or diagnose a health problem; rather, it serves as a preventive or therapeutic solution to address it, sometimes in conjunction with other treatments. A common confusion lies in distinguishing between an NPI and an approach or technique. An approach is too vague and does not accurately describe the content of the NPI, while a technique is too specific, representing only one ingredient of an NPI. A prototypical study allows for the comprehensive description of all characteristics of an NPI, including its health objectives, target population, mechanisms of action, content, implementation context, and the prerequisites for the professional involved.

The connection between mechanistic, interventional, and implementation studies forms the backbone of the epistemological positioning of the NPIS Model regarding the evaluation of NPI. This does not mean that an interventional study, for example, cannot explore biological mechanisms or psychosocial processes. Instead, this backbone provides coherence to the studies and structures the validation process of NPI for integration into a standardized practice framework.

An evidence-based data point is a theoretical or practical knowledge acquired through rigorous and integrated scientific methods and reasoning. The NPIS Model follows this logic in the health field (see Figure 3). It provides specific methodological and ethical recommendations for NPI for studies focusing on their mechanisms and explanatory processes (mechanistic study), their content (prototypical study), their evolution over time (observational study), their benefits and risks (interventional study), and their application and personalization modalities (implementation study).

This criterion was established for the scientific validation of medications. It is impossible to think that psychotherapy led by a psychologist or a diet plan supervised by a dietitian can be concealed from a study participant. Every effort has been made to establish the best causal link between the proposal of a practice and its effects on health, taking into account the specificities of NPI without compromising the expected rigor and ethics of health research. Our recommendations aim to minimize biases and enhance validity and reproducibility. However, this will never prevent some individuals or promoters from committing fraud. Given the lower health risks of NPI compared to rapid-action health products (such as surgery, fast-acting medications, or implantable medical devices) and their potential interest in prevention, pragmatic real-world trials or effectiveness studies best address the consideration of risks. Additionally, the evaluation of an NPI has justified conducting an implementation study within the specific country to avoid extrapolating results from one cultural context to another.

NPI are a field in which many amalgamations occur between scientific knowledge and opinion, due to their objective—human health—and their operational mode, which involves immaterial protocols. However, it is essential to learn to distinguish science from research amidst the multiplication of tools and information channels (Klein, 2020), particularly on the subject of NPI. The same communication channels transmit both scientific knowledge and beliefs, opinions, comments... Information of different statuses becomes intertwined. Knowledge can turn into the belief of a particular community, and vice versa.

Research, on the other hand, pertains to questions for which we do not yet have answers. These well-defined questions still have no answer. A researcher works on the subject using various methods and strategies. Research fosters doubt. Scientific societies work to advance research within a specific territory and theme.

Given that NPI are universal health protocols centered on individuals and administered by humans, an international multidisciplinary scientific society needed to be created. This has been achieved since 2021. This society is called the Non-Pharmacological Intervention Society (NPIS).

The term NPI has been used by scientists working in the health field since 1975. However, it is not the only term; other similar terms are used synonymously, especially in PubMed. There are ten English terms to describe non-pharmacological processes and twenty-eight to describe methods of operation. An exhaustive inventory of NPI on a scientific article search engine is currently impossible due to the variety of terms researchers use, each with distinct meanings: rehabilitation intervention, psychosocial intervention, mental intervention, cognitive intervention, psychological intervention, behavioral intervention, psychosomatic intervention, nutrition intervention, dietary intervention, food intervention, physical intervention, body intervention, exercise intervention, manual intervention, salutogenic intervention, natural intervention, self-help intervention, nursing intervention, therapy intervention, care intervention, disease management intervention, multimodal intervention...

A search on PubMed from August 15, 2024, indicates 55,689 articles citing the term "non-pharmacological" or its equivalent up to 2023. While these figures do not challenge the trend, they are likely underestimated due to the database's focus on health products rather than services, biological treatments over psychosocial ones, studies on North American populations, and journals published by North American organizations. This aligns with an official U.S. government site managed by the National Center for Biotechnology Information and hosted by the National Library of Medicine, part of the National Institutes of Health (NIH).

A search on PubMed from August 15, 2024, also reveals 11,642 articles citing the term "non-pharmacological intervention" or its equivalent up to 2023. Both curves demonstrate an increase since 2000, with a notable acceleration since 2010.

The French National Authority for Health has been encouraging the use of the term NPI in health since 2011.