This is a relatively large blog post. Firstly, I am setting out the rationale, literature and then how two PDA semi- interview questions were developed. Then I am providing links to recent reflections on twitter about PDA, some are more important than others, especially the one detailing how one cannot assume PDA is autism from its original research.


There is contradictory information on how many PDA questions for Diagnostic Interview for Social and Communication Disorders (DISCO) by Lorna Wing and Judy Gould. Some say there are 17 (Christie et al, 2012), others say 15 (Gillberg et al, 2015; O’Nions et al, 2016). Now these original questions have never been published in full and are not included in the 2002 DISCO paper (I checked). Gillberg (2015), states that they used questions already in the DISCO to assess for delayed speech development. It is likely that Gillberg et al (2015) discarded 2 questions that assess for speech delay, as this information was already available from their assessments with full DISCO. Consequently, it was just taken as gospel that there were only ever 15 original PDA DISCO questions (O’Nions et al, 2016).

Wing and Gould developed these original PDA questions in 2002 and from Newson’s unpublished research (Newson’s article is from 2003). These draft PDA items are relatively important as they been used to help develop the EDA-Q (O’Nions et al, 2014), and a 22- question unvalidated semi-structured interview by Liz O’Nions and Francesca Happé (O’Nions et al, 2015; 2018). It makes sense there were 17 original PDA DISCO questions, as the remaining 15 questions do not assess for speech delay (Gillberg et al, 2015), so if one is assessing for PDA in its potential entirety, they would have these two missing questions. Worth mentioning Newson et al (2003) stated in their supporting file:

Clearly no child will show all the behavioural examples listed, any more than all autistic children show the whole repertoire of autistic behaviours; but every child with clear-cut PDA will manifest the overall complex pattern, not merely one or two features.” Page 2.

I.e. that a person does not need to display speech delay to receive a PDA diagnosis, under Newson’s definitions and this is represented in how 10% of her sample had no speech delay (Newson et al, 2003).

I am partly interested in them for comparison purposes to the revised 11 DISCO questions, so for future comparison studies for effectiveness of diagnosing PDA, similar to comparing diagnostic rates between different editions of the DSM-5 (See here for more information: ). Furthermore, the Revised 11 DISCO questions are clinically different to the original ones due to change in wording. The original set had “Socially manipulative behaviour to avoid demands”, (Gillberg et al, 2015, p980), while later has “Apparently manipulative behaviour” (O’Nions, et al, 2016, p415). We know that if a condition has manipulative aspects, this differentiates it to autism (Gillberg et al, 2015; O’Nions et al, 2015). Hence the Revised 11 PDA DISCO questions are more autism like, than the original items, i.e. the two sets of respective PDA DISCO questions are clinically different to each other.

These matters, when most PDA predicted populations are based on Newson’s descriptions, see Christie (2007), Gillberg (2014), and McElroy, (2016), or alternatively Woods (2020). Particularly, pertinent is that the majority of these predictions are from Christopher Gillberg, states that PDA is common (2014) and later with others that PDA might be as common as up to 3% – 5% in some populations (Gillberg et al, 2015). This would be at the low diagnostic threshold they used with the original PDA DISCO items. The original PDA DISCO items are needed to test Gillberg’s predictions most accurately about PDA populations and prevalence rates. Thus, replacing the two probable missing original questions is also required. I have asked the Lorna Wing Centre for these items, but they have not responded, so I am providing an overview of the literature on this speech delay in PDA, from Elizabeth Newson Centre research.

What Elizabeth Newson Centre based research says about Speech Delay.

I reviewed Newson et al (2003) descriptions of for the Language delay, seems result of passivity PDA trait and some unpublished research into speech development by Charlotte Graham-White (2002). These are the notes I made on both pieces of research (Newson et al, was reviewed first):

  • PDA has no coding issues relating to Theory of Mind or Empathy, or in understanding others body language. Coding issues are when a person cannot process or make sense of certain aspects of communication.
  • PDA coding issues relate to identity and obligation.
  • Also, might demand avoidance, direct requests might be an issue (I apologise, this is a vague comment).
  • Persons with PDA tend to take on roles, more than echolalia.
  • Social manipulative behaviours are fully manifest by the age of 5 and half years old, with a large variety of manipulative behaviours displayed.
  • Newson had two groups of PDA infants, the majority were passive (90%), while the minority were active (10%).
  • An individual does not need to a display full list of PDA traits to receive a diagnosis.
  • 90% had speech delay and had contact with a Speech and Language Therapist (SALT), but this contact was potentially not beneficially due to the CYP’s demand avoidance.
  • Most CYP catch up was independent, and done by the age of 6, which is a pre-requisite for the sheer variety of manipulative demand avoidance expressed (later part is my observation).
  • 86% had over the top of “bizarre” language content; it seems language used by CYP with PDA is often atypical and is an important for clinical consideration.
  • Would include aspects on taking on roles/ mimicking; 26% had semi social mimicry and 46% showed social mimicry, typical roles include teacher/ mother/ psychologist.
  • This is my observation. Newson’s clinic saw persons with Specific Language Impairments as part her clinical practice, so also assessed dyslexia and dysphasia, it is rather odd to not compare PDA to these population groups, as she did with the autism spectrum.
  • Much of the descriptions are not related to speech delay.
  • Pragmatics in PDA is not deeply disordered, so pragmatics in PDA are relatively straightforward.
  • Repetitive questioning might be a sign of panic.
  • Failures to code social identity and obligation, leads to a need to not comply. Thus, deficits in identity. I would say not necessarily so. This research appears to have been conducted in 2002, before Newson et al (2003). Newson had competing coding issues. Some PDA features are meant to be driven a need for control, such as lability of mood. I discuss these issues elsewhere:
  • CYP with PDA have problems in recognizing their gender, but this is also seen in autism (my comment on this).
  • Deficits in identity are meant to be able to differentiate PDA from Asperger’s. There appears to some merit to this as the EDA-Q has 9 out of 26 questions relating to proposed deficits in identity and obligation and it can be used to differentiate between autism and PDA (O’Nions et al, 2014).
  • Suggested PDA might be about how some CYP do not understand how others socially interact due to proposed coding deficits.
  • CYP with PDA can have problems understanding humour and metaphors.
  • Assumes a need to use stereotypes to finely differentiate between people.
  • Social identity/ social status/ Pride/ shame deficits are proposed; yet what are we really measuring when we are assessing for such features?
  • Sample contained 58 case files, ages between 5 – 12, that were diagnosed with PDA at the Elizabeth Newson Centre between 1994 – 2001. 32 males, vs 26 females.
  • Had limited investigation of inter-rater bias.
  • If a feature was seen in less than 75% of the sample (44 CYP), the sample was considered too small to give comprehensive results.
  • CYP with PDA can have problems holding joint attention.
  • Speech delay in this sample appears independent from general developmental delays.
  • It is ore the vocabulary used by CYP with PDA is atypical.
  • Notes overlap in pre-verbal development in infants with PDA, overlapping with that seen in autistic infants.
  • Immature pronunciation was a feature.
  • Repetitive speech was an issue.
  • Demand avoidance trait appears to be pervasive, as it impacted speech CYP with PDA displays.
  • Using speech to direct/ avoid/ protest/ distract; would indicate distress behaviours and CYP with PDA trying to assert their self-agency (Moore, 2020).
  • The diagnostic reports had differences in style and content.
  • Do CYP with PDA identify with persons around them?
  • Files did not describe pre-verbal and verbal imitation.

How were the two new PDA interview questions developed?

I consulted a Speech and Language therapist who is interested in PDA for more information on the proposed wording and items for these two new questions. The SALT in question is DISCO trained.

There is one semi-structured interview question that assesses speech delay, in a tool derived from these original PDA DISCO questions. This tool is open access and is available in “Supplemental Table 1: Parent interview questions”, of O’Nions et al (2018), here:

This tool has been adapted to use to diagnose PDA as a standalone diagnostic entity by the Elizabeth Newson Centre, I do not have permission to publish their version of the tool. This is the specific question:

Language delay

• Were you concerned about your child starting to talk later than others born around the same time?

• Once s/he had started talking, did s/he seem to catch up very rapidly?

I removed the first sub-question and replaced it with another more descriptive one. The previous one is not explicit on developmental milestones around speech at ages of two and three, while the later one is. This provides more relevant information for a researcher or a clinician. You can see the current draft version of these two interview questions at the end of this section.

The severity scoring is taking from the open access revised PDA DISCO questions in O’Nions et al (2016), here in “Online Resource 2: Full descriptions of DISCO items included in the final 11-item list.”:

Newson states that PDA social communication is often fine after catching up. The issue is mainly around atypical word content, seems to be linked to taking on roles. I am unhappy with the term of “bizarre” and “atypical” would likely confuse caregivers. After discussing this with the SALT, it was suggested “weird” be used.

I included 2 sub-questions to assess for social mimicry, both verbal and pre-verbal. The pre-verbal question is related to passiveness often seen in PDA infants. While the verbal mimicry is often related to taking on roles.  These questions were included as acting on the suggestion of Graham-White (2002). I have tried to make these questions reflect the original research.

These are the current draft wording for the items, I am currently seeking further input into them. I will update this when finalized. It is important to stress that these two features are not essential for a PDA diagnosis, even under Newson et al (2003) interpretation of PDA.

Gillberg et al (2015) diagnostic threshold was:

A collapsed Total PDA—score summing all (out of the 15) symptoms endorsed (range 0–15 in any given individual)—will also be reported. Individuals with a Total PDA score of 5 or more were—based on clinical experience, not on systematic evidence—considered High-scorers, suggesting that in clinical practice they would have been given a diagnosis of PDA. “Classic PDA” was defined as Total PDA score of 5 or more and including the presence of socially manipulative or shocking behaviour to avoid demands.” Page 981.


Our final PDA decision was not only based on PDA item from DISCO but also from the general impression of

how the avoiding demands was or had been frequent in the participant.” P980

I suspect of research purposes when using original PDA DISCO questions, a comparable threshold to Gillberg et al (2015) would be:

Classic PDA was defined as a total PDA score of 6 or more and including the presence of socially manipulative or shocking behaviour to avoid demands. Although, to me this seems potentially too low, so perhaps at least 7 out of 17, again with the presence of socially manipulative or shocking behaviour, would be better?

Draft Re-Imagined “Newson’s” PDA DISCO questions.

16. Language Delay.
– Was your child using 2-word phrases around the age of 2 and was he using short simple sentences by age 3, like their peers?
– Once s/he had started talking, did s/he seem to catch up very rapidly?
Traits. Language delay, seems result of passivity.Score. 0 Marked 1 Minor 2 No problem
17. Atypical language content and mimicry.
– Do you often find the words A uses to be weird
– Would A show any social imitation before they started talking (e.g. clapping hands, copying an action)?
– Does A show any mimicry (e.g. by acting out roles)?
Traits. Language delay, seems result of passivity. Comfortable in role play and pretending.Score. 0 Marked 1 Minor 2 No problem

I would welcome feedback on these questions.

Other recent twitter musings.

I have been productive in the variety of my reflections on PDA in the last two months, so there about 10 new pdfs of various twitter threads. Going from the first thread since my most recent blog post.

Newson explicitly stated PDA is not an autism spectrum disorder.

The “splitters” are trying to split autism using something that is not autism.

PDA clinical features are often based against autism stereotypes.

Commentary of submission into an Australia clinical guideline for autism assessment.

Some reasons why I use Elizabeth Newson’s PDA research.

Why it is important to use Newson’s later PDA research.

One cannot assume from Newson’s work PDA is part of the autism spectrum.

That moment when you realise, you need to define what you consider to be.

Newson’s views on behavioural based strategies.

Partly why any credible or reputable autism expert should say PDA is NOT autism is probably warranted.


Christie, P., Duncan, M., Fidler, R. & Healey, Z. (2012). Understanding Pathological Demand Avoidance Syndrome in Children: A Guide for Parents, Teachers and Other Professionals. London: Jessica Kingsley Publishers.

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: 769–770.

Gillberg, C., Gillberg C., Thompson, Lucy., Biskupsto, R., & Billstedt, E. (2015). Extreme (“pathological”) demand avoidance in autism: a general population study in the Faroe Islands. European Child & Adolescent Psychiatry, 24(8), 979–984.

Graham-White, C. (2002). An Investigation into the Communication Development and General Communication of children with Pathological Demand Avoidance Syndrome (Unpublished research). Retrieved from:  (Accessed 24 November 2020).

McElroy, R. (2015). PDA – is there another explanation? (Online Magazine). Retrieved from: (Accessed 24 November 2020).

Moore, A. (2020). Pathological demand avoidance: What and who are being pathologized and in whose interests? Global Studies of Childhood, 10(1) 39–52.

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(7), 595–600.

O’Nions, E., Christie, P., Gould, J., Viding, E., & Happé, F. (2014). Development of the ‘Extreme Demand Avoidance Questionnaire’ (EDA-Q): Preliminary observations on a trait measure for Pathological Demand Avoidance. Journal of Child Psychology and Psychiatry, 55, 758–768.

O’Nions, E., Quinlan, E., Caceres, A., Tulip, H., Viding, E., & Happé, F. (2015). Pathological Demand Avoidance (PDA): an examination of the behavioural features using a semi-structured interview (Unpublished research). Retrieved from:’Nions.pdf (Accessed 23 November 2020).

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). European Child & Adolescent Psychiatry, 25(4), 407–419.

O’Nions, E., Viding, E., Floyd, C., Quinlan, E., Pidgeon, C., Gould, J., & Happé, F. (2018). Dimensions of difficulty in children reported to have an autism spectrum diagnosis and features of extreme/‘pathological’ demand avoidance. Child and Adolescent Mental Health, 23(3), 220-227.

Woods, R. (2020). PDA – a new type of disorder? (Online Magazine). Retrieved from:,cent%20of%20the%20human%20population. (Accessed 24 November 2020).

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