; or (3) a physician to recommend, complete forms for, or register veterans for participation in a treatment program involving medical marijuana that is approved by the applicable State. (b) Definitions In this section: (1) Physician The term physician means a physician appointed by the Secretary of Veterans Affairs under section 7401(1) of title 38, United States Code. (2) State The term State has the meaning given that term in section 102 of the Controlled Substances Act ( 21 U.S.C. 802 ). (3) Veteran The term veteran has the meaning given that term in section 101 of title 38, United States Code. (c) Sunset This section shall cease to have force or effect on the date that is five years after the date of the enactment of this Act. 4. Studies on use of medical marijuana by veterans (a) Study on effects of medical marijuana on veterans in pain (1) In general Not later than two years after the date of the enactment of this Act, the Secretary of Veterans Affairs shall conduct a study on the effects of medical marijuana on veterans in pain. (2) Report Not later than 180 days after the date on which the study required under paragraph (1) is completed, the Secretary shall submit to Congress a report on the study, which shall include such recommendations for legislative or administrative action as the Secretary considers appropriate. (b) Study on use by veterans of State medical marijuana programs (1) In general Not later than two years after the date of the enactment of this Act, the Secretary shall conduct a study on the relationship between treatment programs involving medical marijuana that are approved by States, the access of veterans to such programs, and a reduction in opioid abuse among veterans. (2) Report Not later than 180 days after the date on which the study required under paragraph (1) is completed, the Secretary shall submit to Congress a report on the study, which shall include such recommendations for legislative or administrative action as the Secretary considers appropriate. (c) Veteran defined In