. ▁Other ▁proposed ▁causes , ▁such ▁as ▁child hood ▁v acc ines , ▁are ▁controvers ial . ▁The ▁v acc ine ▁hypothesis ▁has ▁been ▁extens ively ▁investig ated ▁and ▁shown ▁to ▁be ▁false , ▁lack ing ▁any ▁scientific ▁evidence . ▁Andrew ▁W ake field ▁published ▁a ▁small ▁study ▁in ▁ 1 9 9 8 ▁in ▁the ▁United ▁Kingdom ▁suggesting ▁a ▁caus al ▁link ▁between ▁aut ism ▁and ▁the ▁tri val ent ▁M MR ▁v acc ine . ▁After ▁data ▁included ▁in ▁the ▁report ▁was ▁shown ▁to ▁be ▁deliber ately ▁f als ified , ▁the ▁paper ▁was ▁ret ract ed , ▁and ▁W ake field ▁was ▁struck ▁off ▁the ▁medical ▁register ▁in ▁the ▁United ▁Kingdom . ▁ ▁It ▁is ▁problem atic ▁to ▁compare ▁aut ism ▁rates ▁over ▁the ▁last ▁three ▁dec ades , ▁as ▁the ▁di agnostic ▁criteria ▁for ▁aut ism ▁have ▁changed ▁with ▁each ▁revision ▁of ▁the ▁Di agnostic ▁and ▁Statist ical ▁Man ual ▁( DS M ), ▁which ▁out lines ▁which ▁sympt oms ▁meet ▁the ▁criteria ▁for ▁an ▁AS D ▁diagn osis . ▁In ▁ 1 9 8 3 , ▁the ▁D SM ▁did ▁not ▁recognize ▁P DD - N OS ▁or ▁As per ger ’ s ▁synd rome , ▁and ▁the ▁criteria ▁for ▁aut istic ▁dis order ▁( AD ) ▁were ▁more ▁restrict ive . ▁The ▁previous ▁edition ▁of ▁the ▁D SM , ▁D SM - IV , ▁included ▁aut istic ▁dis order , ▁child hood ▁dis integr ative ▁dis order , ▁P DD - N OS , ▁and ▁As per