(a) Any person convicted of a second or subsequent offense under this Act may be sentenced to imprisonment for a term up to twice the maximum term otherwise authorized, fined an amount up to twice that otherwise authorized, or both.(b) For purposes of this Section, an offense is considered a second or subsequent offense, if, prior to his or her conviction of the offense, the offender has at any time been convicted under this Act or under any law of the United States or of any State relating to controlled substances. Amended by P.A. 097-0334,§ 5, eff. 1/1/2012.