Cognitive remediation in residential substance use treatment: A randomized stepped-wedge trial

Executive dysfunction is common in individuals with substance use disorder (SUD) and presents a barrier to treatment engagement. The study aimed to investigate the effectiveness of cognitive remediation (CR) for improving executive functioning and treatment retention in patients with SUD, using a stepped-wedge cluster randomized controlled trial. The sample included 527 adults enrolled across ten residential SUD treatment providers in NSW, Australia. The intervention consisted of 12 hours of CR delivered over six weeks in a group format. The comparator was treatment-as-usual (TAU). Primary outcomes included self-reported executive functioning and proportion of treatment completed (PoTC), measured as the number of days in treatment divided by the planned treatment duration. Intention-to-treat analysis did not find significant differences for self-reported executive functioning (mean difference = -2.49, 95%CI [-5.07, 0.09], p = .059) or PoTC (adjusted mean ratio = 1.09, 95%CI [0.88, 1.36], p = .442). Due to high dropout from the intention-to-treat sample (56%) a post-hoc analysis was conducted using a per-protocol approach, in which CR was associated with improved self-reported executive functioning (mean difference = -3.33, 95%CI [-6.10, -0.57], p = .019) and improved likelihood of treatment graduation (adjusted odds ratio = 2.43, 95%CI [1.43, 4.11], p < .001). More research is required to develop a CR approach that results in service-wide treatment effectiveness.