Extreme demand avoidance (EDA/PDA)

Definition

When one hears (or rather sees) the abbreviation PDA used nowadays, they typically associate it with the term "Public Display of Affection," thus thinking of when people are physically intimate with each other in the presence of others. However, for those working as clinicians or researchers in the fields of developmental neurology, paediatrics, psychiatry, or clinical psychology, their primary associations may lean towards a different direction. A group of children presents with a rather peculiar type of oppositional behaviours, sometimes now categorised under the term "pathological demand avoidance" syndrome, increasingly referred to as PDA or EDA ("extremely demand avoidance"). Boys and girls with "this kind of PDA" will do almost anything to avoid meeting the demands placed upon them by both adults and other children. The behaviours "used" to maintain avoidance range from openly oppositional or manipulative to "extreme shyness," passivity, and mutism. These behaviours, in terms of expressing affection, are almost the opposite of those we associate with the usual meaning of PDA. However, the avoidance behavior is often "publicly displayed," without any noticeable sense of the inappropriateness in the sometimes even exhibitionistic style of extreme demand avoidance. In recent years, it has been suggested that the "p" in PDA be replaced with "e" to emphasise that it involves extreme demand avoidance rather than a "pathological" behaviour.

Childhood-onset PDA/EDA (which will be referred to as EDA throughout the rest of this post) has been suggested to be a variant of autism spectrum disorder (ASD) or oppositional defiant disorder (ODD), but it is more likely that any of various early symptomatic syndromes giving rise to disorders of developmental neuropsychiatry (ESSENCE), including language disorder, mild intellectual disability, ADHD, ODD, and/or ASD, could be either an underlying or associated problem with EDA. Alternatively, it could be the reverse: PDA is not a variant of any of these deviations but represents a relatively unique behavioural phenotype with multiple "comorbidities," similar to any other "paediatric psychiatric deviation."

Background and research

PDA was first mentioned in 1980 when Elisabeth Newson, in a speech to the East Midland section of the British Paediatric Society, presented the first twelve cases of what she considered to be a "new" and separate syndrome which she termed PDA. Despite attracting considerable clinical attention in the UK and other parts of Europe (including Scandinavia), virtually no research has yet been published in the field (Newson et al., 2003, Gillberg et al 2024). Experienced clinicians in both child psychiatry and pediatric neurology and paediatrics testify to its existence and the very significant problems encountered in interventions and treatment. O’Nions and colleagues (2014) have developed a "trait measure" for EDA (the "EDA-Q" form), a measure that appears very promising for both research and clinical practice. The tool they have developed is a parent questionnaire with 26 questions/items that seem easy to use and have preliminary good-to-excellent psychometric properties. Although the EDA-Q form needs validation in studies involving other (especially clinically diagnosed) groups of children and adolescents, and from other researchers, it seems to mark a breakthrough in the - hitherto almost entirely neglected - systematic research on an important clinical problem (Gillberg et al 2024).

Prevalence and comorbidity

EDA is not something that only occurs in ASD or ODD or as a "separate entity." According to 50 years of clinical experience and research experience in Gothenburg, Stockholm, London, Glasgow, New York, Bergen, Odense, Torshavn, Cape Town, and Kōchi, it is not at all uncommon in language disorder, ADHD (especially the inattentive variant "ADD"), selective mutism, school refusal, anorexia nervosa, specific behavioral phenotype syndromes/"rare health conditions" (including 22q11 deletion syndrome and Marfan syndrome), and epilepsy (Reilly et al 2014). It is highly likely a term that would almost perfectly match the phenotype of the Japanese "diagnosis" Hikikomori. Although there are currently no major population studies of EDA except for a small one in the Faroe Islands (Gillberg et al 2015), it is apparent that it is not an extremely rare phenomenon.

Intervention and treatment

EDA is already a very tangible clinical problem, not only in Europe but worldwide. Interventions and treatment currently rely almost exclusively on qualified guesses, clinical experience, and trial-and-error. EDA is one of the most challenging constellations of problems within the entire field of child and adolescent psychiatry. Strategies developed for ASD, ODD, or ADHD are often ineffective, and parents, teachers, and clinicians may be driven half-mad by the child's stubborn refusal to cooperate and by avoidance, "manipulative," and sometimes shocking behaviours.

Looking ahead

There is a need for a comprehensive and concerted clinical research effort in this area. We need systematic information on diagnostic boundaries/criteria, prevalence, gender distribution, pathogenesis, comorbidity, natural history, and treatment. It would probably help if the "condition" were generally renamed EDA, not only to avoid confusion with Public Display of Affection but also because it is undisputedly the case that while the avoidance is extreme, there will always be individuals who have difficulty determining whether the avoidance is "pathological" or not.