Predicting engagement in working memory training for methamphetamine use disorder: indices of motivation, attention, and achievement

RationaleImpulsivity and inefficient self-regulation are major deficits in substance use disorder, corresponding to lack of treatment response and low abstinence rates. Prefrontal cortex (PFC) executive functions, such as working memory (WM), enable self-regulation of impulsivity by keeping in mind cognitive strategies for optimal decisions about future action. Training WM may improve self-regulation of impulsivity in various populations, including methamphetamine use disorder (MUD) patients. However, many controversies exist regarding the efficacy of WM training (e.g. near-versus far-transfer effects) and associated improvements to clinical outcomes. Such controversies may relate, as observed in our preliminary study in MUD patients, to variation in WM training engagement. MethodsIn this nested examination of n=17 male MUD patient data (age range 20-39 years) from a previously published study, the primary aim was to identify variables that may predict a WM training engagement index (EI), and secondarily to determine if EI could predict clinical improvement in MUD patients. The EI consisted of three domains of WM training: motivation, attention/learning and achievement, and we examined the link between self-report measures of impulsivity, self-regulation, anxiety/depression and executive function and EI. ResultsThose with higher rates of attention/learning demonstrated greater improvement in attentional impulsivity, and those with higher rates of achievement had a significant improvement in self-reported anxiety, as well as slower time to complete an executive function task after treatment. DiscussionWe suggest the EI is a useful measure to detect level of engagement during WM training in patients with MUD and is predictive of clinical improvements.