; and (C) by amending paragraph (3), as redesignated by subparagraph (A) of this paragraph, to read as follows: (3) The term eligible caregiver parent means a caregiver parent who has been admitted to a program operated pursuant to subsection (a). ; and (15) in subsection (r), by striking to fiscal years 2001 through 2003 and inserting for fiscal years 2019 through 2023 . 5. Effectiveness of stimulant treatment methods (a) Research The Director of the National Institute on Drug Abuse shall conduct research, directly or through contract with another entity, on the effectiveness of the use of agonist and antagonist drugs to reduce the problems associated with stimulant abuse, including cocaine and methamphetamine abuse. (b) Authorization of appropriations There are authorized to be appropriated such sums as may be necessary to carry out this section for fiscal years 2019 through 2023. 6. IOM Study on drug treatments for stimulant abuse (a) Report The Secretary of Health and Human Services shall seek to enter into a contract with the Institute of Medicine of the National Academies to complete a literature review and submit a report to Congress on the effectiveness of agonist and antagonist drugs for the treatment of stimulant abuse, including cocaine and methamphetamine abuse. (b) Authorization of appropriations There are authorized to be appropriated such sums as may be necessary to carry out this section for fiscal years 2019 through 2023. 7. GAO Evaluation of the impact of this legislation (a) Study on the level of funding for treatment The Comptroller General of the United States shall conduct a study on— (1) the impact of the programs authorized by this Act (including the amendments made by this Act) on the effectiveness and availability of treatment for heroin, opioids, cocaine, methamphetamine, 3,4-methylene­dioxy­meth­am­phet­amine, and phen­cy­cli­dine abuse