In this subchapter:
(1) "Controlled Substances Act" means the federal Controlled Substances Act (21 U.S.C. Sec. 801 et seq.).
(2) "Convicted" includes an adjudication under juvenile proceedings.
(3) "Drug offense" has the meaning assigned under 23 U.S.C. Section 159(c) and includes an offense under Section 49.04, 49.07, or 49.08, Penal Code, that is committed as a result of the introduction into the body of any substance the possession of which is prohibited under the Controlled Substances Act.