20 CFR § 404.350 - Who is entitled to child's benefits?
(4) You are unmarried; and
(5) You are under age 18; you are 18 years old or older and have a disability that began before you became 22 years old; or you are 18 years or older and qualify for benefits as a full-time student as described in § 404.367.
(b) Entitlement preclusion for certain disabled children. If you are a disabled child as referred to in paragraph (a)(5) of this section, and your disability was based on a finding that drug addiction or alcoholism was a contributing factor material to the determination of disability (as described in § 404.1535) and your benefits ended after your receipt of 36 months of benefits, you will not be entitled to benefits based on disability for any month following such 36 months regardless of the number of entitlement periods you have had if, in such following months, drug addiction or alcoholism is a contributing factor material to the later determination of disability (as described in § 404.1535).