I nearly passed out when in nursing school and watching brain surgery. I felt like I was hyperventilating with the mask on. It almost happened again during another surgery when I smelled the cauterization...that smell grosses me out!
These outward physical appearances are not always the case for all meth users. I worked in a rehablilitation center for 4 years and it is very surprising. I have seen everyday people come in for tx of meth with none of those signs. Even the heaviest users of them. Many were even high ranked professionals...well groomed ....etc.