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”.