Twenty-one years ago, Lask and colleagues first described pervasive refusal syndrome (PRS) as a child's "dramatic social withdrawal and determined refusal to walk, talk, eat, drink, or care for themselves in any way for several months" in the absence of an organic explanation. PRS has been conceptualised in a variety of ways since then. These have included a form of post-traumatic stress disorder, learnt helplessness, 'lethal mothering', loss of the internal parent, apathy or the 'giving-up' syndrome, depressive devitalisation, primitive 'freeze', severe loss of activities of daily living and 'manipulative' illness, meaning the possibility that the children have been drugged to increase chances of asylum in asylum-seeking families. Others have insisted that PRS is simply depression, conversion disorder, catatonia or a factitious condition. This paper reviews these conceptualisations, explores some of the central complexities around PRS and proposes a neurobiological explanatory model, based upon autonomic system hyper-arousal. It touches upon the clinical implications and suggests a new name for the condition reflecting what we believe to be a more sophisticated understanding of the disorder than was available when it was first described.