This is a duplicate of a question asked on Parenting.stackexchange.com, that I'm reposting on this site because I want an answer to this, too. I've never heard of anything like this before, I always heard of Methamphetamine ruining somebody's life/ health. In this case, it seems to be making it better:
"My 16 year old son used to take weed, XANAX, and Adderall and I was easily able to tell when he was high on any of them. He somehow managed to get a medical marijuana prescription so now I just have to let go of the fact that he can smoke weed.
"He recently moved on to methamphetamine and I have no way of telling weather he is high or not. I tried comparing Adderall reviews to methamphetamine and from what I garnered meth is the same as Adderall but without the side effects such as the speedy talking and weirdness, but much higher neurotoxicity.
"We have a hidden camera in our kitchen and I saw him take meth on the kitchen table. When I came home I tried noticing any signs of him being high, but I couldn't find any. Unlike Adderall, he talked completely normally. He did all his homework and chores and even took pride in it, and on top of that studied math even when he didn't have to. He normally finds all of that boring and rarely does it. I didn't want to let him know we had a camera in the kitchen, and I didn't want him to think that the completion of his chores and homework was a sign of him using drugs, so I stayed quiet. He was up until 4am practicing for a test that he had 2 days later, and whenever I walked in, he wasn't playing any video games and actually studying. I have never seen him this way (working so hard without going behind our back to play games), but again, I don't want to make him think its a sign that he using meth.
"His grades changed to A's and B's once he started using meth, but I know how neurotoxic it is, and that the long term effects are extremely terrible, and I hate to admit it but meth turned him into a better person, but only when he's on it, when he gets off it he is much worse then he was before.
"Eventually I asked him straight-up if he was any drugs besides what I knew, and whenever he is on meth he is extremely honest so he admitted to his use. He claimed it isn't a problem and that he takes 40mg every 2 days orally and that he lets the comedown happen, but I know that meth is really bad long term so I don't want him taking it.
"Does anyone know how to tell if someone is high on meth besides the fact that he is working on chores and homework?"
Credit to kirill2485 for the OP.