; 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 law of the applicable State or Indian Tribe. (b) Definitions In this section: (1) Indian land The term Indian land means any of the Indian lands, as that term is defined in section 824(b) of the Indian Health Care Improvement Act ( 25 U.S.C. 1680n ). (2) Indian Tribe The term Indian Tribe has the meaning given that term in section 4 of the Indian Self-Determination and Education Assistance Act ( 25 U.S.C. 5304 ). (3) Physician The term physician means a physician appointed by the Secretary of Veterans Affairs under section 7401(1) of title 38, United States Code. (4) State The term State has the meaning given that term in section 102 of the Controlled Substances Act ( 21 U.S.C. 802 ). (5) 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. Research on use of medical marijuana by veterans (a) Research on effects of medical marijuana on veterans (1) In general Not later than 180 days after the date of the enactment of this Act, the Secretary of Veterans Affairs shall support clinical research on the use of medical marijuana— (A) by veterans to manage pain