The science behind the PDA controversy - Part 4
This is the fourth installment in a series investigating the science behind Pathological Demand Avoidance (PDA). In the first part, I talked about the controversy behind PDA. In the second part, I went into detail about the origins of PDA and investigated whether it is even a real phenomenon. In the third part, I looked at whether PDA could be attributable to autism alone. If you haven't read parts 1, 2 and 3 yet, I definitely recommend going back to them first.
In part 4, we’ll investigate what conditions (other than autism) might be underlying PDA symptoms, and what research backs those connections.
Conditions Linked To PDA
We’ve already discussed the strong assumption that PDA is caused by autism. We’ve seen the circularity in the evidence for that view, and we’ve discussed the evidence suggesting that there is more to the PDA picture than autism alone. But autism isn’t the only condition tied to the cluster of traits known as PDA. The few studies looking at PDA outside of the autistic population have found interesting results.
Studies have found associations between PDA and anxiety, ADHD, antagonism, emotional instability, antisocial personality disorder, conduct disorders, callous-unemotional traits, and epilepsy. And some studies have even found that anxiety, ADHD, antagonism and emotional instability were more predictive of PDA than autism was. Some argue that PDA may emerge from one or multiple of these conditions, perhaps in conjunction with autism or perhaps unrelated to it.
PDA has also been noted as bearing a strong resemblance to Oppositional Defiant Disorder (ODD). A 2021 overview found that some cases of PDA also met the criteria for ODD.
Still, some argue against tying these two disorders together. O’Nions argues that using the label ‘defiant’ might imply that avoidance and demand-related behaviors are a result of the child’s wilfulness, which could prime caregivers to respond reactively to assert their authority. She argues that the mechanisms underpinning avoidance are notably different than in disruptive behavior disorders like ODD. and are more related to the need to regulate the intense emotions experienced with demands than they are willful defiance.
Still, it’s important to note that research suggests ODD is overdiagnosed in black children, and that this is likely because of racist assumptions about these children’s intentions. ODD’s DSM criteria includes language that assumes the diagnoser knows the child’s internal state. There are criteria that the child “deliberately annoys others” or “is vindictive" – things that no one but the child could really know. Methodologically, these criteria are extremely questionable and, in my view, should be removed entirely to avoid the potential for increasing biased diagnoses. Beyond these differences in intention, the rest of the ODD criteria such as seeming emotionally reactive and refusing to comply with authority figures, seems to map pretty directly onto traits associated with PDA.
So is PDA just ODD without the stigmatizing assumptions about intention? Could we simply fix the ODD diagnosis to remove these already problematic criteria and not need to add PDA as its own diagnosis? Possibly. Still, PDA as currently formulated seems to have additional criteria to ODD, such as engaging in imaginative roleplay and fantasy, using social strategies and being good at getting others to do what they want.
Still, on the view that PDA represents multiple co-occurring conditions, it’s possible that ODD represents a piece to this puzzle. One that, as described in part 2, has been found to be a statistically significant cluster of traits separate from autism and adhd.
Only more research will answer these questions, and there currently isn’t much. But given the strong overlap in criteria, it seems important to keep investigating the connection between these two.
If PDA and ODD are the same thing, we need to use that insight as a way to challenge the misconceptions about those diagnosed with ODD. We have a responsibility to dismantle systematic factors leading PDA and ODD diagnoses to be made on racial lines. And most importantly, regardless of PDA, we need to keep advocating against assuming the intentions of the children diagnosed with ODD. These kids suffer far greater stigmatization and discrimination as a result of their diagnosis – and the fact their diagnoses rely on the diagnosing physician's psychic insight into their intentions is an injustice that we shouldn’t ignore.
Could PDA come from anxiety or trauma?
There are many conditions linked to PDA. But a significant chunk of research points to an association between PDA and anxiety.
A 2020 study by Stuart et al. found that demand avoidant behavior in children with PDA could be understood as an attempt to increase certainty and predictability, and thus alleviate the anxiety over uncertainty. In the study, children with PDA used varying strategies depending on the level of anxiety provoked by the demand, suggesting that the demand avoidant behavior was happening in response to the anxiety. This also fits how many people with PDA report experiencing it- as an intense anxiety response to demands.
As Woods points out in a 2020 paper, anxiety is not an autism symptom, but is rather a comorbidity of autism, affecting 42-56% of autistic people. Research suggests that anxiety in autism can be affected by the environment that the autistic person is in - specifically having to adapt to a cultural environment that is often not well suited to us, and a sensory environment that triggers a lot of discomfort.
Anxiety in autism is also exacerbated by co-occurring ADHD which may worsen the gap in fit between the individuals and their environment. Something like autism plus ADHD could account for the extreme levels of anxiety seen in those who meet the PDA criteria. PDArs levels of anxiety are in the top 2% of the human population. Woods suggests trauma could also be a potential factor in driving this heightened level of anxiety.
In a 2021 paper, Kildahl et al explain that repeated trauma from misattunement with caretakers could occur in autistic people as a result of the double empathy problem. This problem describes how the differences between how autistic and non-autistic people think and perceive the world can lead to misunderstandings in both directions. Historically, autistic people were seen as lacking the ability to understand the minds of non-autistic people, but recent research has shown that non-autistic people also fail to understand autistic people.
If your caretakers repeatedly misunderstand you, attribute meanings to your behavior that aren’t what you intended, and subject you to situations that (while perfectly fine for most people) feel torturous to you – that can be very traumatic. Kildhl et al suggests that this could lead to the kind of intense anxiety and intolerance to uncertainty that is seen in the PDA population.
Unfortunately, the double empathy problem also impacts how we study PDA and autism. As Kildahl et al point out, most of the studies use caretaker reports rather than first person reports. Still, it is hard to see the caretakers' reports as validly representing their children’s experience when the double empathy research suggests they will likely do a poor job of understanding what their child’s internal experience is.
Still, despite these methodological concerns, research continues to point to anxiety and intolerance of uncertainty as important predictors of PDA.
A 2023 survey-based study conducted on the general population found that both autistic traits and anxiety were important predictors of PDA traits, but anxiety was the most predictive factor.
A 2023 study that actually surveyed adults with PDA found that both anxiety and intolerance of uncertainty were predictive of meeting the EDA-QA PDA criteria. They also found that anticipatory responses to uncertainty played a big role in demand avoidant behaviors for adults.
A 2024 study found that children with PDA were likely to have a co-occurring anxiety disorder or high levels of reported anxiety. But interestingly, these children had less demand avoidant behaviors after their anxiety was treated with fluoxetine.
In my view, these studies represent some of the best quality research that’s been done on PDA and should not be discounted. They are relatively strong evidence that PDA is driven by anxiety, and even offer hope that treating anxiety could reduce PDA symptoms.
The totality of the evidence seems to point towards a sort of hybrid origin of PDA –that it emerges when anxiety levels are high, and autism or some other condition makes demands particularly challenging or traumatic. This ties together most of the main theories on PDA and fits well with the current evidence.
Do PDArs Respond To Treatments Differently?
Still, what about those who argue that PDA responds differently to clinical interventions than the other conditions or diagnoses offered as explanations of PDA? After all, the label emerged, in part, because patients weren’t benefiting from the current treatments for their other diagnoses. Clinicians such as Gillberg, with decades of clinical experience, report that PDA is one of the most difficult to treat phenomena he has encountered, and often strategies developed for autism, ADHD or ODD are ineffective - leaving parents, clinicians and teachers without ways to help. White et al make similar points, suggesting that clinicians may be identifying a practical distinction between PDA and other conditions that isn’t being translated in the research.
Interestingly, one study found that parents mostly rated PDA focused clinicians and other professionals as helpful in working with their PDA identified children. This adds some support to the idea that PDA oriented professionals are finding interventions to help these children in ways not yet studied in the literature.
Still, others argue that the best strategies for PDA are also best practices for anxious or autistic people in general. Kildahl argued in 2021 that if PDA is a manifestation of autism, anxiety, or trauma, assuming that it is simply its own syndrome could block people from accessing treatments for these conditions that are already well-established.
Stuart and Grahame similarly argued in 2020 that understanding PDA as an anxiety driven response to intolerance of uncertainty would allow access to anxiety treatments. It would also destigmatize demand avoidant behavior, shifting the understanding from an irrational defiance to a response to very real anxiety.
In 2018, Green argued that a common approach should be adopted for all children being assessed for autism, regardless of whether they had been identified as PDA. In this approach, a rigorous assessment of the child’s characteristics, environment, and co-occurring mental health disorders should be used to individualize interventions at home and in education settings.
Woods argues similarly in 2018, pointing out general autism strategies such as the SPELL Framework and the Low Arousal Approach that mirror the common suggestions for PDArs. He suggests that practices that promote autonomy, low-demands, and emotional regulation education can help not only PDArs but autistic people in general. Rather than push these for only PDArs, we should also be educating all autistic people and caretakers of autistic people to use these strategies. In addition, more research needs to be done using non-circular methodologies to learn what helps PDArs symptoms improve.
The recent study on the use of fluoxetine in children with PDA also suggests that it may be possible to treat PDA symptoms with drugs that target anxiety.
So maybe the real problem is that those fitting the PDA criteria are not being connected to the RIGHT treatments for autism or anxiety for them. Maybe they need strategies like SPELL and the Low Arousal Approach, or even anxiety medication, but are instead being redirected into programs like Applied Behavioral Analysis, until their demand avoidance is identified.
Again, only more research will answer these questions. But until we have those answers, creating individualized treatment plans based on the symptoms arising for the person may be more appropriate than relying on “one size fits all” treatments for autism or anxiety.
To give myself as an example, anxiety medication has somewhat helped my symptoms. But taking a lower demand approach has been life changing. My PDA symptoms were seen as anxiety alone, and my autism and ADHD weren’t recognized until later on. So for most of my life, this approach was never suggested. It was only in the PDA discussions online that I found this resource. I often wonder what my life would have looked like if myself and my caretakers had understood this need early on. I also wish that therapists were taught to recognize demand avoidance as something that might indicate conditions beyond anxiety could also be present.
We still don’t have conclusive answers on what causes PDA, but there is strong evidence that it is related to heightened anxiety, often in the context of autism, ADHD or other underlying conditions.
So after going over all this research, how should we understand PDA and the science on it? Should we consider it to be its own condition? Should we keep using a unique label for it? How should we talk about it online spaces? I’ll give my thoughts on these questions in part 5, the final article in this series.
This article is the fourth in a series investigating the science behind PDA. You can find Part 5 “Continuing The Conversation On PDA ” here.
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