Amarantus Bioscience (OTCPK:AMBS) has a compound called Eltoprazine that they are investigating in adult ADHD and other indications. A previous study in ADHD showed somewhat mixed results. While Eltoprazine is in Phase 3, Amarantus has struggled significantly as a company and had its stock delisted. It now trades on OTC Pink and is a very risky investment. I expect Eltoprazine to eventually be acquired by another company which may or may not pursue it in ADHD.

https://seekingalpha.com/amp/article/4101422-...stimulants