Section 4251, added Pub. L. 89–793, title II, § 201, Nov. 8, 1966, 80 Stat. 1442; amended Pub. L. 91–513, title III, § 1102(s), Oct. 27, 1970, 84 Stat. 1294; Pub. L. 92–420, § 3, Sept. 16, 1972, 86 Stat. 677, defined terms for purposes of this chapter.

Section 4252, added Pub. L. 89–793, title II, § 201, Nov. 8, 1966, 80 Stat. 1443, related to examination to determine if offender is an addict and likely to be rehabilitated through treatment.

Section 4253, added Pub. L. 89–793, title II, § 201, Nov. 8, 1966, 80 Stat. 1443, related to commitment for treatment.

Section 4254, added Pub. L. 89–793, title II, § 201, Nov. 8, 1966, 80 Stat. 1443, related to conditional release.

Section 4255, added Pub. L. 89–793, title II, § 201, Nov. 8, 1966, 80 Stat. 1443; amended Pub. L. 95–537, § 3, Oct. 27, 1978, 92 Stat. 2038; Pub. L. 99–570, § 1861(c), Oct. 27, 1986, 100 Stat. 3207–53; Pub. L. 99–646, § 19, Nov. 10, 1986, 100 Stat. 3596, related to supervision in the community.

Repeal effective Nov. 1, 1987, and applicable only to offenses committed after the taking effect of such repeal, with sections to remain in effect for five years as to an individual who committed an offense or an act of juvenile delinquency before Nov. 1, 1987, and as to a term of imprisonment during the period described in section 235(a)(1)(B) of Pub. L. 98–473, see section 235(a)(1), (b)(1)(C) of Pub. L. 98–473, set out as an Effective Date note under section 3551 of this title.