5 % ▁to ▁ 7 0 %, ▁a ▁wide ▁variation ▁illustr ating ▁the ▁difficulty ▁of ▁assess ing ▁aut istic ▁intelligence . ▁An x iety ▁dis orders ▁are ▁common ▁among ▁children ▁with ▁AS D , ▁although ▁there ▁are ▁no ▁firm ▁data . ▁Sym pt oms ▁include ▁generalized ▁anx iety ▁and ▁separation ▁anx iety , ▁and ▁are ▁likely ▁affected ▁by ▁age , ▁level ▁of ▁cogn itive ▁function ing , ▁degree ▁of ▁social ▁imp air ment , ▁and ▁AS D - specific ▁difficulties . ▁Many ▁anx iety ▁dis orders , ▁such ▁as ▁social ▁ph ob ia , ▁are ▁not ▁commonly ▁diagn osed ▁in ▁people ▁with ▁AS D ▁because ▁such ▁sympt oms ▁are ▁better ▁explained ▁by ▁AS D ▁itself , ▁and ▁it ▁is ▁often ▁difficult ▁to ▁tell ▁whether ▁sympt oms ▁such ▁as ▁comp uls ive ▁checking ▁are ▁part ▁of ▁AS D ▁or ▁a ▁co - occ urr ing ▁anx iety ▁problem . ▁The ▁pre val ence ▁of ▁anx iety ▁dis orders ▁in ▁children ▁with ▁AS D ▁has ▁been ▁reported ▁to ▁be ▁anywhere ▁between ▁ 1 1 % ▁and ▁ 8 4 %. ▁Ep ile ps y , ▁with ▁variations ▁in ▁risk ▁of ▁ep ile ps y ▁due ▁to ▁age , ▁cogn itive ▁level , ▁and ▁type ▁of ▁language ▁dis order ; ▁ 5 – 3 8 % ▁of ▁children ▁with ▁aut ism ▁have ▁com orb id ▁ep ile ps y , ▁and ▁only ▁ 1 6 % ▁of ▁these ▁have ▁rem ission ▁in ▁ad ul th ood . ▁Several ▁met abol ic ▁defect s , ▁such ▁as