Question- Which non-controlled substance, derived from a tropical tree native to Southeast Asia may, at low doses, produce stimulant effects with users reporting increased alertness, physical energy, and talkativeness and at high doses high doses, sedative effects. Some cases of psychosis resulting from the use of this substance have been reported as well.
Answer- The above describes the substance known as Kratom, also known as thang, kakuam, thom, ketum and biak. While this substances has not been scheduled, it is not approved for any medical use and the DEA has listed it as a “Drug and Chemical of Concern.”
(https://www.dea.gov/pr/multimedia-library/publications/drug_of_abuse.pdf; accessed February 2018)