A more holistic approach to autism using the International Classification of Functioning: The why,what,and how of functioning

A commitment to implementing a holistic approach to humans in research and practice appears implicitly or explicitly in the mission statements of most academic, clinical, social, and educational organizations. Even most professionals would likely agree that this is how they seek to approach service users and research participants they encounter. Claiming to work holistically is ambitious, and I doubt that I have ever seen it genuinely occur. Honestly, I do not know what precisely a truly holistic approach should and could look like, and I am confident that few know the answer to this question. That said, I suppose that a holistic approach should ideally be one that aims to picture the person’s body, mind, situation, and context, and derives service which conveys deep individual understanding and is consistent with the person’s own perspective, preferences, and needs.

Unfortunately, the driving forces that dictate how things are done are not mission statements or good intentions but budgets, traditions, ideologies, bureaucracy, and paradigms that professionals prefer or feel obliged to use. Despite these obstacles, I am convinced that we could work far more holistically if we apply the appropriate frameworks. In this editorial, I will try to persuade you that the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF; WHO, 2001, 2007) is the logical and adequate choice for such a framework. It has holistic qualities, the necessary authority, and is more or less waiting to be implemented—with specific recent developments in relation to autism.

Currently, the frameworks autism professionals most often relate to are the diagnostic systems Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) and International Classification of Diseases (11th Revision; ICD-11). In recent decades, these manuals have tremendously impacted how practitioners and researchers, think about autism. There are advantages to using these systems; for example, they define and operationalize the phenomena in question, improving communication and standardization of research. They also facilitate effective administrative processes and routine data collection. However, they surely do not provide a holistic understanding of unique individuals in their world. On the contrary, diagnosis seeks to condense individual information to a circumscribed entity, with the risk that an individual is perceived primarily within these confines.

With long wait times and insufficient resources, limiting assessment to checking off diagnostic criteria outlined in these diagnostic systems is a top priority. This focus over-shadows evaluation of other dimensions of an individual and their context, which are necessary to more holistically understand the client and plan meaningful tailored support. Assessment cannot stop with assigning a signpost. Instead, diagnosis must be the starting point for collecting individual information on strengths and challenges and the facilitating and hindering factors in the individual’s everyday environment. This approach would at least approximate the notion of working holistically. In the best case, such assessments would not necessarily require a diagnosis and would take place outside clinical settings, that is, in education, social services, and working life.

While the American Psychiatric Association only provides a classification system for mental conditions, an objective of the WHO is to provide nomenclatures for all conditions, factors associated with well-being, and interventions from an international and cross-disciplinary perspective. One of the WHO’s most important classifications is the ICF, which categorizes almost 1700 aspects of functioning, operationalizing human body functions and structures (a person’s somatic and psychological prerequisites and potential), activities (what a person is doing or not doing in their life), participation (social and societal involvement), and environmental factors (the micro, meso, and macro context). There are multiple ways in which this framework is ideal for application to holistic autism research and practice. It applies a biopsychosocial model of functioning, embracing the fact that these domains are interactive and all relevant to living a good life (Pellicano et al., 2022). It also uses accessible language, bridging disciplines and enabling communication with stakeholders. In the ICF, the primary perspective of people on their own functioning and ways to improve it is highly valued. It is an established system for goal-setting in somatic rehabilitation (e.g. cerebral palsy, encephalitis), but its value for mental health and neurodevelopmental conditions is slowly being recognized.

The construct of “functioning” has negative connotations in some countries and is disliked by some autistic people, probably because it is regularly conflated with impairment or dysfunction, a purely negative operationalization of functioning attributed to a person and their productivity. In autism, functioning terminology has additionally been misused to denote average to high intelligence (“high functioning”) or low intelligence (“low functioning”) (Alvares et al., 2020). If we can agree to set these historic misuses aside, functioning is essentially neutral and noncausal. It could be defined as a person’s performance arising from interactions between their individual strengths and challenges, and the facilitating and hindering factors in a given context. Assessment of functioning using the ICF to complement diagnosis has many potential benefits. Importantly, functioning profiles address real-life challenges and directly map on to supportive solutions, such as strengths-based actions, removal of environmental barriers, and preservation or further development of environmental facilitators. For authorities, a standardized functional view may enable a more effective and fairer calculation of service-related costs than diagnosis-related ones (Hopfe et al., 2018; Schraner et al., 2008). Finally, functioning is not the exclusive domain of clinicians and is therefore far more accessible than diagnostic labels for non-clinical setting such as schools or residential care homes. This is decisive for achieving a holistic approach to autism in wider parts of society.

Unfortunately, functioning does not automatically tell us about a person’s well-being or quality of life, which must ultimately be viewed the most important outcome of holistic work. Nevertheless, many of its functional domains are known to be closely related to well-being, such as sleep (Deserno et al., 2019), self-regulation (Dijkhuis et al., 2017), the built environment (Black et al., 2022), and school and work life (International Society for Autism Research, 2018; Leifler et al., 2022). The biopsychosocial functioning model of the ICF is also compatible with positive psychology and strengths-based approaches (Seligman & Csikszentmihalyi, 2000), as well as influential dimensional research paradigms, such as Research Domain Criteria (RDoc) (Insel et al., 2010) and transdiagnostic clinical science (Astle et al., 2022; Fletcher-Watson, 2022). Finally, and of importance to the integrity of the autism community, the ICF model of functioning may offer an opportunity to reconcile the apparently irreconcilable neurodiversity and biomedical approaches to autistic behaviors (Bölte et al., 2021).

One might argue that functioning is already captured as part of autism diagnostic assessment. Indeed, both the DSM-5 and ICD-11 recommended the use of tools such as the World Health Organization Disability Assessment Schedule (WHODAS) (Park et al., 2019) or the ICF generic code set (Prodinger et al., 2016) as a mechanism to prove the diagnostic criterion of “impairment.” Previously, DSM-IV and ICD-10 recommended that practitioners deploy the Global Assessment of Functioning Scale (Aas, 2011) or Children’s Global Assessment Scale (Shaffer et al., 1983). Other tools are also frequently applied to assess functioning, most prominently the Vineland Adaptive Behavior Scales (Sparrow et al., 2005). However, there are several limitations to the use of these instruments. First, they are often only applied to corroborate a hypothesis of qualitative impairment, which is a diagnostic criterion in diagnostic manuals. Second, they are crude and often focus only on one domain of functioning (Activities in the ICF model), neglecting to capture individual strengths or the role of the environment. Third, they are generic and were developed to assess functioning aspects across conditions. They are neither autism-specific nor cover the areas of functioning most crucial to autistic individuals. A more consequent and appropriate ICF-based evaluation of individual functioning is therefore recommended by an increasing number of international authorities and guidelines, either generally for conditions involving functional challenges (Swedish Board of Health and Welfare, 2019) or specifically for autism (Whitehouse et al., 2018). That national authorities now strongly recommend ICF implementation signals a shift toward more holistic assessment.

There are barriers to implementing the ICF in research and practice. Many researchers, professionals, stakeholders, and decision-makers are unaware of it or are unwilling to endorse it. Especially in psychiatry, I have met a significant lack of interest or resistance to the ICF and its role in assessment, which is perceived as irrelevant to clinical diagnosis—another sign of the dominance of the DSM and ICD systems. One legitimate critique is that the ICF’s comprehensiveness makes it laborious and time-consuming to use. To tackle this issue, the WHO and the ICF Research Branch generated a research pipeline for ICF Core Sets, which are—short versions of the ICF, containing only those categories that have demonstrated significance for a certain condition. Identifying such categories is a rigorous process comprising a systematic literature review, an expert survey, a qualitative study, a clinical study, and a multidisciplinary and expertise-based consensus conference process (Selb et al., 2015). In 2017, my team, in collaboration with a steering committee, researchers, clinicians, and stakeholders from all WHO regions, completed this process and published ICF Core Sets for autism, containing less than 7% of the total ICF and with more than half of categories reflecting participation and environmental factors (Bölte et al., 2019). Thereafter, we and others started to evaluate these Core Sets for validity in different settings (e.g. university, employment), across cultures, during the Covid-19 pandemic, and contrasted them against other ICF Core Sets with convincing results (Black et al., 2019; Fridell et al., 2022; Schiariti et al., 2018; Thompson et al., 2021; Viljoen et al., 2019). More recently, we have translated and operationalized the ICF Core Sets to a set of scorable items (self- and informant ratings) and implemented them on an Internet platform that generates results, sorted for individual strengths and challenges along with environmental barriers and facilitators, in real-time. The reader can find more information on this work, in the form of short movie explainers at icfcoresets.se/en. At the time of writing, we have finalized a pilot of the platform and collected quantitative data on preliminary psychometrics, norms, and item-level analysis, as well as qualitative data on user experience in several hundred autistic and neurotypically developing children and adults. Similar studies are also planned in the United Kingdom and Germany. These evaluations are an iterative and non-trivial process that will lead to further improvement of the platform. Such work is needed to maximize the feasibility of the ICF in practice.

In summary, while a holistic understanding of autistic people is consistent with the mission statements of autism organizations, and self-conceptions of many professionals in the field, it is not practiced. Despite being essential for planning and implementing individualized support, diagnostic manuals and tools dominate and fail to embrace holism. Clinical diagnoses, in particular, focus on individual impairment, neglecting the potential strengths of an individual and the significance of the environment for their situation. Application of the ICF, and especially ICF Core Sets, can move us toward the goal of a holistic understanding of autism. This approach should replace assessment that primarily seeks to confirm or reject suspicion of an autism diagnosis, representing a shift from a biomedical model approach to a biopsychosocial one. However, there are undeniable obstacles to this, both practical ones, such as the need of redoing the structure and processes of service systems and skilling-up a massive number of professionals in ICF use, and psychological and political ones, such as the sluggishness and the power interests of professions and organizations. The ICF is not perfect, and there are numerous other great ideas for changing research and practice in autism, but I believe with a comparably lower chance of breaking through the noise. To me, the formal authority of the ICF, in addition to its useful model, is a strong argument for its implementation.