Austism is a Spectrum...and like JJ said.... the environment/security etc has a huge bearing....autism is about 'impairments'.... and though not classic autistic- even my 'HFA' vary depending on what and where they are....and if ever i doubt their diagnosis.... it is quickly made apparent as soon as something 'rocks the boat'...and there are times when in a 'snapshot' moment...mine appear 'classic autist'....
i'm sure you meant severity...as all of us have 'struggles and successess'....but i cannot bring myself to say which autism is the 'baddest'!!!!
when i llok at my 3.... all affected differently....ds1 is the one that can be the most socially challenging....ds2 has the worst emotional reactions.....and ds3 has the most literal understanding.....so between them some days can be quite a challenge.... howver...individually they are all classed as 'less severe'.... but i always imagine that a severly autistic child would have ALL this rolled into one...and the added frustration of little verbal language&few people who understand them...