Moving, eating, drinking, sleeping, talking, reading, writing, painting, listening to music, watching a movie, dancing, laughing, walking, singing, meditating, gardening, socializing, etc., are all activities of daily life. Some of these can generate joy, pleasure, personal growth, and well-being. In a democratic country, everyone is free to interpret and experience these activities in their own way. This relates to life philosophy, lifestyle, the art of living, and personal development. In other words, a daily activity is not an intervention, even if it can occasionally and randomly contribute to the health of certain individuals. Occupational activities and treatments for health problems identified by medicine are different.

The following products are not considered NPI:

• Hygiene and beauty products (shampoo, toothpaste, brush, body cream, etc.)
• Natural products (plants, food, mushrooms, essential oils, etc.)
• Health products (medications, implantable biological materials, dietary supplements, etc.)
• Medical devices (artificial organs, prosthetics, orthotics, digital applications, monitoring systems, etc.)

The following goods and services are not considered NPI:

• Cultural products or services (video games, books, podcasts, artistic practices, museum visits, theater, writing, etc.)
• Everyday consumer products or services (haircuts, aesthetic treatments, dining out, etc.)

The following actions are not considered NPI:

• Public health promotion activities (communication campaigns, videos, posters, booklets, websites, social media posts, etc.)
• Architectural adaptations (creating access ramps, etc.)
• Environmental adaptations (reforestation of a park, creation of a sports workshop, etc.)

The following approaches are not considered NPI:

• Professional disciplines (physiotherapy, psychology, dietetics, public health, etc.)
• Educational approaches (personal development, etc.)
• Esoteric practices (spiritual practices, religious worship, divination, witchcraft, etc.)

The following organizations are not considered NPI :

• Health organizations (networks, platforms, clinics, health centers, healthcare establishments, etc.)
• Health systems (digital platforms, etc.)

The following measures are not considered NPI :

• Health policies (strategies, plans, programs, etc.)
• Regulations (decrees, laws, etc.)
• Judicial decisions (warnings, convictions, etc.)

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.

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).

As of April 2019, there were 46 evaluation models for NPI in the scientific literature (Carbonnel and Ninot, 2019). These models were constructed by researchers for researchers, often from a monodisciplinary perspective and rarely from a patient-centered approach. This led to significant heterogeneity in study protocols and the way NPI were conceived (approach, method, technique, or materials). The results were scattered, debatable, poorly transferable, and rarely reproducible. Consequently, these practices were not widely recognized outside the study context (dependent on the establishment and/or practitioner). This situation raised doubts about their effectiveness (e.g., efficacy, safety, relevance, utility, cost-effectiveness), their content (e.g., heterogeneity in doses, procedures, ingredients, techniques, contexts, target populations), their approval (e.g., ethics committees), their dissemination (e.g., conflicting reviewer opinions), their teaching (e.g., protocols, best practices), and their recognition (e.g., authorization, integration into official classifications, reimbursement). This lack of a consensual evaluation model for NPI suggested that each professional had to reinvent their program for every new patient, given the wide or contradictory recommendations from authorities, agencies, and scientific societies. It also implied that only the patient-provider relationship mattered in the health effects induced (Ninot, 2020). Moreover, it left the door open for pseudoscientific practices and, more broadly, parallel medicine, along with all the obscurantist, health-related, sectarian, political, and judicial issues that are known in France (Miviludes, 2022; CNOI, 2023; CNOM, 2023) and around the world (Ernst and Smith, 2018). This idea was also gaining traction in the United States in the field of oncology, aiming to juxtapose two medical offerings: one based on experimental science, primarily focused on surgery, medication, radiotherapy, and medical devices, and the other described as "complementary, integrative, or traditional," based on individual experience, opinions, and traditions (Mao et al., 2022). This second offering claimed exclusivity in the domains of prevention and care, emphasizing care for the person versus cure for the disease. Thus, the NPIS Model was co-constructed with the idea that experimental science could demonstrate the existence of effective, safe, and reproducible prevention and care protocols. This work was supported by seed funding for participatory research from INSERM and involved over 1,000 participants under the guidance of a committee of 22 multidisciplinary experts, including two user representatives. This transdisciplinary innovation is currently supported by 30 French scientific societies, the National Center for Palliative Care and End of Life, INCa, and the French Platform for Clinical Research Networks.

Each NPI file in the NPI Registry has been submitted by a practitioner or researcher through the dedicated platform hosted by the NPIS. Each file undergoes review by an independent and integrated scientific committee. This committee invites relevant scientific societies and health authorities to validate the NPI files and/or to oversee the decisions made. Each validated file is then reviewed by a committee of users and professionals. Once labeled NPIS©, the file is translated into at least English and French and integrated into the NPI Registry.

The file contains standardized content supported by scientific studies that align with the NPIS definition of NPI, the expected specifications (Table 2), and the consensual evaluation framework for NPI, known as the NPIS Model. It includes a manual for professionals, an information notice for users, a section on funding options, and an area for anonymous user feedback. This ensures the file remains dynamic and part of a virtuous cycle of continuous improvement for the NPI.

A minimum of one prototypical study, one mechanistic study, two interventional studies, and one implementation study published in a peer-reviewed journal is required for an NPI proposal to be accepted by the expert committee tasked with validating the NPI file and awarding the NPIS© label. Specifically, experts must have evidence to anonymously vote on each criterion of the NPI file proposed to the NPIS by a submitter:

• Described (≥ 1 prototypical study)
• Explainable (≥ 1 mechanistic study)
• Effective (≥ 2 interventional studies)
• Safe (≥ 2 interventional studies)
• Implementable (≥ 1 implementation study in the country)

A professional must understand all the specifics of the NPI, the criteria justifying its use, how to implement its protocol, whom to contact, useful tips, required materials, and any prerequisite training needed.