Pathological demand avoidance (PDA)
Christopher Gillberg gives an overview of Pathological demand avoidance (PDA), including definition, background and research, prevalence and comorbidity, and intervention and treatment.
When you hear (or rather see) the acronym PDA being used these days, you usually associate it with shorthand for “Public Display of Affection” and you think about acts of physical intimacy in the view of others. If you work as a clinician or researcher in the field of neurodevelopment, paediatrics, psychiatry, or clinical psychology, it is possible that your primary associations may take a different route. A group of children presents with a rather peculiar type of oppositional behaviours, sometimes now subsumed under the label of “pathological demand avoidance” syndrome, also increasingly referred to as PDA. Boys and girls with “this kind of PDA” will do anything to avoid meeting demands of adults and children alike. The behaviours “used” in maintaining avoidance range from openly oppositional or manipulative to “extreme shyness”, passivity, and muteness. These behaviours in terms of expression of affection are rather the opposite of those associated with the commonly used meaning of PDA. However, the avoidant behaviour is quite often “publicly displayed” and with no feeling for the inappropriateness of the, sometimes even, exhibitionist style of extreme demand avoidance (EDA).
Childhood onset PDA (which will be what is assumed when referring to PDA in the remainder of this text) has been suggested to be a variant of autism spectrum disorder (ASD) or of oppositional-defiant disorder (ODD), but it is more likely that any kind of early symptomatic syndrome eliciting neurodevelopmental clinical examinations (ESSENCE) (Gillberg, 2010), including language disorder, mild intellectual disability, ADHD, ODD, and/or ASD could be the underlying or associated problem in PDA. Or, it could be the other way around: PDA is not a variant of any of these disorders but represents a relatively unique behavioural phenotype with multiple comorbidities, much like any other “child psychiatric disorder”.
Background and research
The “disorder” was first heard of 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 believed to be a ”new” and separate syndrome and that she referred to as PDA. Even though PDA has attracted quite a bit of clinical attention in the UK and other parts of Europe (including Scandinavia), virtually no research has been published in the field so far (Newson et al., 2003). Experienced clinicians throughout child psychiatry, child neurology, and paediatrics attest to its existence and the very major problems encountered when it comes to intervention and treatment. O’Nions and co-workers (2014) have developed a “trait measure” for PDA (“the EDA-Q”), a measure that appears to hold considerable promise for research, and clinical practice. The instrument that they have developed is a 26-item parent questionnaire that appears to be easy to use and with preliminary good-excellent psychometric properties. Although the EDA-Q is in need of validation in studies on other (particularly in clinically diagnosed) groups of children and adolescents, and by other researchers, it already appears to mark a breakthrough in the – hitherto almost completely neglected – systematic study of an important clinical problem. It is to be hoped that the whole instrument will soon be published and made available to bona fide researchers, and at the next stage to clinicians.
Prevalence and comorbidity
PDA is not just encountered in ASD or ODD or as a “separate entity”. According to 40 years of clinical and research experience in Gothenburg, Stockholm, London, Glasgow, New York, Bergen, Odense, Torshavn, and Kōchi, it is not at all uncommon in language disorder, ADHD (particularly inattentive subtype or “ADD”), selective mutism, school refusal, anorexia nervosa, certain behavioural phenotype syndromes (including 22q11 deletion syndrome and Marfan syndrome) and epilepsy (Reilly et al 2014). It is, very likely, a label that would fit almost perfectly with the phenotype of the Japanese “diagnosis” of Hikikomori. Even though no prevalence estimate of PDA yet exists, it is clearly not an extremely rare phenomenon.
Intervention and treatment
PDA is already a very real clinical problem, not just in Europe, but across the planet. Intervention and treatment currently rest almost exclusively on guess-work, clinical experience, and trial-and-error. It is one of the most “difficult-to-treat” constellations of problems in the whole of child and adolescent psychiatry. Strategies developed for ASD, ODD, or ADHD are often ineffective and parents, teachers, and clinicians may be driven half-crazy by the child’s stubborn refusal to cooperate and by avoidant, manipulative, and exhibitionist-style shocking behaviours.
There is a need for a concerted and comprehensive clinical research effort in the field. We need systematic information about diagnostic boundaries/criteria, prevalence, gender ratio, pathogenesis, comorbidity, natural outcome, and treatment. It would probably help if the “condition” be renamed EDA (Extreme Demand Avoidance), not just so as to avoid confusion with PDA (Public Display of Affection), but because there can be no argument that the demand avoidance is extreme, but there will always be those who will have problems determining if the avoidance is pathological or not.