I thought ADHD couldn't really be diagnosed until 7 y.o.? Anyway, I agree with everyone above about getting a second opinion. Other things I'd look at, if you haven't already: the DSM criteria to see if *you* think they apply
http://www.cdc.gov/ncbddd/adhd/diagnosis.html , and yet another book, the Eides' The Mislabeled Child. And as someone mentioned, it might not be a bad idea to have the vision angle checked out with an optometrist from
http://www.covd.org/Home/AboutVisionLearning/ADHDVision/tabid/112/Default.aspx .
Dumb question re: impulsivity that you've probably already thought of, but is she getting enough sleep? (could there be allergies getting in the way of sleep? This is something I'm currently exploring with one of my kids who is driving us all nuts for no apparent reason in an impulsive sort of way; he has allergies and really swollen tonsils for months on end and it finally occurred to me - duh - that perhaps it's interfering with his sleep, making him overtired - he's super-wired. I'm anxiously awaiting our next checkups with the ped and allergist though of course they aren't for a few more months)
Putting things in her mouth does sound sensory (I agree about finding an OT place that specializes in SPD - try here
http://www.spdfoundation.net/directory/index.html )
As for the strangulation hazards, that doesn't seem out of the ordinary to me - I'm constantly telling my kids to take them off lol.
just my two cents
