Commentary: Anxiety and behaviour in and beyond ASD; does the idea of 'PDA' really help? - a commentary on Stuart et al. (2020).

Many children with austism spectrum disorder (ASD) show difficulties containing anxiety, acute distress, behavioural avoidance or control, and sometimes to an extreme degree. Not nearly enough is known about the variety of likely origins of such presentations or their course. Pathological Demand Avoidance (PDA) has been advocated as a discrete developmental syndrome explaining such characteristics when extreme, but its status as an entity is controversial and to date poorly evidenced. Stuart et al. make one of the first studies into factors underlying PDA, by testing Intolerance of uncertainty and anxiety as explanatory paradigms. There is a circularity in their sampling design and common respondent methods, which, alongside the uncertain status of PDA itself, inevitably limits firm conclusions from their study. However, they do develop important concepts and hypotheses that could and should be tested in representative samples across ASD, using comparative, longitudinal and intervention designs. This will contribute to important progress will be made in understanding mental health presentations in ASD and their treatment, as well as resolving debates around PDA itself.