RecruitingBehavioural interventionMood and Decision-making in Methamphetamine Use DisorderIn this project, the investigators examine behavior and associated brain activity during explore-exploit decision-making tasks performed pre- and post-modulation of affective state using autobiographical memory recall. The investigators hypothesize that a positive memory recall will reduce negative affective state, reduce explore-exploit biases and normalize the associated brain activity. The investigators propose a randomized double-blind, sham-controlled trial of positive autobiographical memory recall with 80 adults (n=40 per arm) with methamphetamine use disorder (MUD) currently involved in abstinence only treatment centers.