illegal use of drugs
(1) In general The term “illegal use of drugs” means the use of drugs, the possession or distribution of which is unlawful under the Controlled Substances Act [ 21 U.S.C. 801 et seq.]. Such term does not include the use of a drug taken under supervision by a licensed health care professional, or other uses authorized by the Controlled Substances Act or other provisions of Federal law.
42 USC § 12210(d)(1)
None identified, default scope is assumed to be the parent (subchapter IV) of this section.