i would also like to mention to you other signs that my daughter has even if she wasn't high at the time.
~very red around the nose...(she snorts more than she shoots)
~low self-esteem
~lose of appetite
~sleeps alot
~the pupil thing is a dead give away, by the way
hope these things help you...good for you for being perceptive enough to "see" it.
i didn't. i made excuses for all the definate "signs" of an addict. but i am a mom, & moms never want their kids to be addicts.
good luck to you