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PDA: Current Understanding and Future Research Directions

By Dr. Michelle Garnett and Professor Tony Attwood

PDA behaviour can be extremely perplexing. The person persistently and obsessively avoids everyday tasks that they were able to complete on previous days, have the skill to complete, and there are no obvious characteristics of the task that would provoke fear. Completing these tasks would make everyone’s life easier, including their own, and sometimes the tasks they choose to avoid are activities they enjoy or agree need to be completed. So why will the person just not do them?! In this article we explore our current understandings of why PDA occurs and outline future directions for research that are needed to further explore this particular profile of autism.

PDA and Anxiety

Kildahl and colleagues (2021) overviewed 13 studies on PDA in children that met their inclusion criteria, to control for methodological rigour. As one of their research questions, they explored the relationship between PDA and anxiety. This is a highly relevant question since avoidant behaviours generally tend to occur in the context of high levels of anxiety, and anxiety is highly prevalent in autism (Kerns et al, 2020). Only 2 out of 8 cross-sectional studies reviewed measured anxiety and each found that PDA was correlated with higher levels of anxiety than in the autistic group (O’Nion’s, Viding et al, 2014; Stuart et al al, 2020).

One study (Gore Langton & Frederickson, 2016) interviewed parents and uncovered themes relating to the need for certainty, and certain responses to uncertainty. Of the three case studies included in the review only one measured possible co-occurring psychiatric conditions (Reilly et al, 2014) and of the four children aged 5-10 years old none met the criteria for anxiety or depression, however, anxiety can present differently in autistic children and the signs may have been missed by parents.

Currently, there is a lack of studies that explore the associations between PDA and anxiety or trauma. All the studies reviewed by Kildahl and colleagues relied on parental information and did not ask the person with PDA about their anxiety. It is a difficult area of study because autistic children show anxiety in ways that differ from non-autistic children and are less likely to be able to self-report that they feel anxiety due to problems with interoception and/or alexithymia, or language issues.

The conceptualisation of PDA as a distinct condition may reasonably require that the profile is not explained by other conditions, such as anxiety and/or depression, and/or trauma-related- disorders. These conditions also involve pathological (or dysfunctional) levels of avoidance. One concern raised by researchers is that if PDA becomes a neurological explanation for behaviours that may be caused by anxiety or trauma, there is a risk that the underlying emotional difficulties will not be adequately addressed or treated (Orm et al, 2019).

In summary, there are definite links between PDA and anxiety, as cited above, but the relationship has not been fully explored and is not fully understood. Current clinical conceptualisation (for e.g. Christie & Fidler, 2018z) places anxiety at the core of the inability to follow everyday demands, i.e. avoidance of the demand is due to the need to be in control in order to manage overwhelming anxiety about not being in control. A person with PDA will describe their inability as a “freeze” experience, as one woman recently said to one of us (MG), “My brain literally can’t do it. It is not a choice; I simply cannot do it.” And as one adolescent girl recently said with tears of despair coursing down her cheeks, “I don’t understand why I can’t do ordinary things like everyone else can, like go to school and have a shower and do my chores, but I just can’t.”


Nature versus Nurture

There has been no research on studying demand avoidance behaviours as complex social phenomena from a transactional perspective. Currently, our understandings of PDA place the difficulties within the individual, which obscures our understanding of the influence of their context. (Milton, 2013, Orm et al, 2019). All social communication occurs within a dynamic and the dynamic will influence the response of each person within the social interaction. In transactional accounts of autism, development is understood to be shaped by the types of responses we encounter whilst interacting with others (Mitchell, 2017). Perhaps because of the mortifyingly painful error in psychiatry of describing the cause of autism as being because the mother does not love her child enough (for e.g. Bettelheim, 1967), there have been few research studies on how parenting and the family environment affect the social developmental trajectory of autistic children. We know that autism is not entirely genetic and that the brain is highly plastic, especially in the early years of development, leading to the inevitability that early social experiences will impact brain development. It would be very helpful for both autistic individuals and their families to understand from research the best parenting practices that support autism in the family.

An example of a transactional account of autism is the concept of “the double empathy problem” (Milton, 2012) which postulates that autistic people struggle to find a place in society not only because of their own innate struggles to infer the mental states of non-autistic others but also because others struggle to infer their mind states, that is, there is a misunderstanding on both sides. In line with a “double empathy problem” perspective, the child with PDA may be misinterpreted as a naughty, defiant, rude, and disrespectful child due to the persistent nature of their refusal to comply with many seemingly reasonable adult requests. As a consequence, discipline is frequently applied, which may involve, at best, calm verbal correction and withdrawal of privileges, and on less optimal parenting days, shouting, complaints about the child and their behaviour, e.g. “you need a lot of social skill training,” “why do you always make things so difficult,” or worse. Both the parent and the child feel “not good enough” and over time their relationship may deteriorate.

If we consider that the PDA defiance is due to “freeze” or “fight” because of high levels of anxiety and is enacted without consideration of the impact of their behaviour on the family or the classroom due to cognitive empathy problems, the child’s anxiety will likely increase with the typical parenting strategies described. The child may begin to feel less safe in the family if the punishment is perplexing to them, especially if it involves shouting, due to sensory sensitivity and high levels of affective empathy for a negative atmosphere. Many families experience this pattern for years prior to diagnosis and understanding of PDA, and there is a lot of damage that has inadvertently occurred in the relationship that needs to be repaired.

Within such interactions, the misattunement experienced can lead to increased levels of anxiety in both parent and child, leading potentially to more PDA-type behaviours which are considered disruptive and socially inappropriate and lead to more negative social sanctions and consequences. Some researchers have proposed that these transactional factors may exacerbate or maintain PDA behaviours (Davis & Crompton, 2021; Mitchell et al, 2021), but there is no suggestion that these parenting practices cause PDA. In fact, even when more ‘gentle parenting’ practice has been adopted from an early age, that is the parenting style has been adapted to the child’s needs, to the extent that the family works well together when the child is in school and demands increase, then the intolerance to demands is more obvious (Sally Russell OBE, 2023, personal communication).


Research Directions

There are many areas to further explore to further understand PDA. We need more studies to explore:

  • How can we reliably assess for PDA?
  • Are there any physical markers for PDA such as brain morphology?
  • What is the relationship between PDA and anxiety?
  • What is the relationship between PDA and ADHD?
  • Is anxiety a driver of demand avoidance and, does the treatment of the anxiety reduce demand avoidance?
  • What transactional patterns, if any, increase or decrease demand avoidance?
  • What parenting practices lead to the best outcomes for children with PDA?
  • How do we measure PDA in adults?
  • How do we best support adults with PDA?


Where to from Here?

If you are interested in learning more about PDA, whether you are a parent or a professional, we have created two 3-hour courses to help:

PDA and Autism: The purpose of this training is to increase your understanding of PDA to assist you to recognise the profile your child, student or client, to increase your confidence in your role with these children and equip you with strategies to maximise positive outcomes.

PDA for Professionals: We assume the knowledge presented in the first course and go deeper to explore strategies and how to best support the PDA-er and their family or partner.



There are many resources available. These are some of our favourites:

Online Resources:

The PDA Society in the UK has developed a library of helpful, evidence-based resources on PDA and we recommend these

PDA Society

For e.g. we highly recommend their Practice Guidance Document as a start:

Practice Guidance Document

Dr Ross Greene, American Psychologist has developed a model of care called Collaborative & Proactive Solutions (CPS) which is based on research and practice and based on collaboration and compassion. He does not use the term PDA, but instead talks about kids for whom challenging behaviour occurs when the demands and expectations being placed on them exceed their capacity to respond adaptively. His website has excellent practical resources for parents, teachers and health professionals.

Books: Children and teenagers:

Collaborative Approaches to Learning for Pupils with PDA: Strategies for Education Professionals (2018) by Ruth Christie and Phil Fidler, published by Jessica Kingsley Publishers.

Super Shamlal – Living and Learning with Pathological Demand Avoidance (2019) by K I Al-Ghani, published by Jessica Kingsley Publishers.

Dr Ross Green (2021). The Explosive Child [Sixth Edition]: A New Approach for Understanding and Parenting Easily Frustrated, Chronically Inflexible Children. Published by Harper Collins, US.

Books: Adults:

Being Julia: A Personal Account of Living with PDA (2021). By Ruth Fidler and Julia Daunt. Published by Jessica Kingsley Publishers.

PDA by PDAers: From Anxiety to Avoidance and Masking to Meltdowns (2019). Ed. Sally Cat. Published by Jessica Kingsley Publishers.

PDA Paradox; The Highs and Lows of My Life on a Little Known Part of the Autism Spectrum. (2019). By Harry Thompson. Published by Jessica Kingsley Publishers.

There are many more wonderful books on PDA that we can recommend, as listed on this web page of the PDA Society:

PDA Society Book List



Bettelheim, Bruno. The Empty Fortress: Infantile Autism and the Birth of the Self. New York: Free Press, 1967.

Calvo F, Karras BT, Phillips R, Kimball AM, Wolf F. Diagnoses, syndromes, and diseases: a knowledge representation problem. AMIA Annu Symp Proc. 2003;2003:802. PMID: 14728307; PMCID: PMC1480257.

Christie, R. & Fidler, F. (2018). Collaborative Approaches to Learning for Pupils with PDA: Strategies for Education Professionals. Jessica Kingsley Publishers, London, UK.

Eaton, J. & Weaver, K. (2020). An exploration of the Pathological (or Extreme) Demand Avoidant profile in children referred for an autism diagnostic assessment using data from ADOS-2 assessments and their developmental histories. GAP, 21 (2), 33- 51

Gillberg C. (2014). Commentary: PDA – Public display of affection or pathological demand avoidance? Reflections on O’Nions et al. (2014). Journal of Child Psychology and Psychiatry, 55(7), 769–770.

Gore Langton E., Frederickson N. (2018). Parents’ experiences of professionals’ involvement for children with extreme demand avoidance. International Journal of Developmental Disabilities, 64(1), 16–24.

Kerns C. M., Winder-Patel B., Iosif A. M., Nordahl C. W., Heath B., Solomon M., Amaral D. G. (2020). Clinically significant anxiety in children with autism spectrum disorder and varied intellectual functioning. Journal of Clinical Child & Adolescent Psychology. Advance online publication.

Kildahl, A. N., Helverschou, S. B., Rysstad, A. L., Wigaard, E., Hellerud, J. M., Ludvigsen, L. B., & Howlin, P. (2021). Pathological demand avoidance in children and adolescents: A systematic review. Autism, 25(8), 2162–2176.

Milton D. E. (2012). ‘Natures answer to over-conformity’: Deconstructing pathological demand avoidance. Autism Experts.

Milton D. E. (2013). ‘Natures answer to over-conformity’: Deconstructing pathological demand avoidance. Autism Experts.

Mitchell, P. (2017). Mindreading as a transactional process: Insights from autism. In V. Slaughter & M. Rosnay (Eds.), Environmental influences on ToM development, (pp. 157– 172). Hove, UKPsychology Press.

Newson E, Le Maréchal K, & David C. (2003). Pathological demand avoidance syndrome: a necessary distinction within the pervasive developmental disorders Archives of Disease in Childhood; 88:595-600.

Orm S., Løkke J. A., Løkke G. E. H. (2019). Pathological Demand Avoidance: en transaksjonell atferdsanalytisk forklaringsmodell uten patologi [Pathological demand avoidance: A transactional behaviour analytic explanatory model without pathology]. Norsk Tidsskrift for Atferdsanalyse, 46(1), 29–43.

O’Nions E, Christie P, Gould J, Viding E, Happé F (2014) Development of the ‘Extreme Demand Avoidance Questionnaire’ (EDAQ): preliminary observations on a trait measure for pathological demand avoidance. J Child Psychol Psychiatry 55:758–768

O’Nions, E, · Gould, J, · Christie, P, · Gillberg, C. Viding E, & · Happé, F. (2016)  Identifying features of ‘pathological demand avoidance’ using the Diagnostic Interview for Social and Communication Disorders (DISCO), Eur Child Adolesc Psychiatry 25:407–419 DOI 10.1007/s00787-015-0740-2

Reilly C., Atkinson P., Menlove L., Gillberg C., O’Nions E., Happe F., Neville B. G. (2014). Pathological demand avoidance in a population-based cohort of children with epilepsy: Four case studies. Research in Developmental Disabilities, 35(12), 3236–3244.

Sally Russell OBE (2023, personal communication). Chair of the PDA Society, UK.

Stuart L., Grahame V., Honey E., Freeston M. (2020). Intolerance of uncertainty and anxiety as explanatory frameworks for extreme demand avoidance in children and adolescents. Child and Adolescent Mental Health, 25(2), 59–67.