Viding et al (Reference Viding, Frick and Plomin2007) made no reference to autistic psychopathy (Reference AspergerAsperger, 1944) nor did any of the other papers in Supplement 49 on assessment risk and outcome in severe personality disorder. The severe unempathic conduct and aggression problems were well recognised by Asperger (Reference Asperger1944) and overlap with what Viding et al (Reference Viding, Frick and Plomin2007) describe as ‘more severe, aggressive, and stable pattern of antisocial behaviour and a specific neurocognitive profile indicative of defects in affect processing’. This is precisely what children (and adults) with autistic psychopathy and antisocial behaviour demonstrate (Fitzgerald, Reference Fitzgerald2001, Reference Fitzgerald2003).