Yes. We have had that issue as well. My son has been on medications since he was 8. It is really frustrating. My son has been faking taking his meds off and on for the last two years (that is the time frame I have been trying to solve this problem, so if anyone has any good solutions for you I would love to hear them.)
I doubt your son’s resistance is for the exact same reasons, but as my son and I have talked about it, his concerns are 1) He doesn’t have any appetite at all, but is hungry all day long. The hunger bothers him, but he can’t make himself eat. 2) He doesn’t feel like “himself” on the medicine. He mentally understands why he needs to be on the medicine, but for a kid who is impulsive and doesn’t naturally value future over present, the long term benefit never is worth the short term side effect.
We recently switched to the patch, hoping for more compliance. He seems slightly more compliant with them- his grades have gone up and he is able to do his homework- but he says the hunger issue is still there and has noticed more irritability, which I have noticed as well.
So, no real solutions to the issue, but sending lots of empathy.