; and (2) in section 304(a) ( 21 U.S.C. 824(a) ), by adding at the end the following: A registration pursuant to section 303(f) issued to a practitioner who is required to comply with section 303(k) may be denied or revoked by the Attorney General upon a finding that the practitioner has failed to comply with section 303(k). . (b) Effective date The amendments made by subsection (a) shall take effect on the date that is 180 days after the date of enactment of this Act. (c) Sunset Effective on the date that is 5 years after the date of enactment of this Act, the following provisions are repealed: (1) Subsection (k) of section 303 of the Controlled Substances Act ( 21 U.S.C. 823 ), as added by subsection (a)(1) of this section. (2) The sentence added by subsection (a)(2) of this section to the end of section 304(a) of such Act ( 21 U.S.C. 824(a) ). 3. Report to Congress Not later than 2 years after the date of enactment of this Act, the Comptroller General of the United States shall submit a report to Congress on the effects of this Act and the amendments made by this Act, including an analysis of— (1) whether there has been a reduction in the volume of opioids prescribed; (2) whether there has been an increase in the likelihood that opioid-dependent patients receive substance use disorder treatment; (3) whether there has been a reduction in opioid-related overdoses and deaths; (4) whether training required by this Act and the amendments made by this Act has changed prescribing practices and increased patient referrals to treatment; and (5) the extent to which prescribers have conformed their practices to those recommended in training pursuant to this Act and the amendments made by this Act.