Decision-making tendencies and voucher spending independently support abstinence within contingency management for methamphetamine use disorder.

Decision-making tendencies and spending within cash voucher-based interventions have individually been shown to be related to future abstinence among participants with methamphetamine use disorder (MUD), but less is known of their independent contributions. This study of participants in a contingency management (CM) trial investigated whether decision-making and spending were each associated with future abstinence. Thirty-two outpatients with MUD, predominately male (68%) and mixed ancestry (94%) with a median age of 34 years, participated in an 8-week cash voucher-based CM pilot trial. Prior to commencing the trial, participants completed a computerized Iowa Gambling Task (IGT) to measure decision-making preferences for more frequent rewards and longer term gains of greater magnitude. Spending and abstinence of participants were tracked over the duration of the trial. In a secondary analysis, time-lagged counting process Cox Proportional Hazard models were conducted. Baseline decision-making, characterized by a preference for frequent rewards, was associated with a greater likelihood of future spending, Hazard Ratio; HR = 1.13 [1.06: 1.21]. Avoidance of short-term rewards to realize longer term, higher magnitude rewards, and spending at the prior visit were each associated with abstinence on the trial, HR = 1.12 [1.03: 1.22] and HR = 1.32 [1.08: 1.61], respectively. Controlling for decision-making, spending, and cumulative abstinence, prior abstinence remained the largest predictor of future abstinence, HR = 3.85 [2.88: 5.16]. Decision-making tendencies and spending are correlated yet independently associated with abstinence reinforcement in CM. Findings highlight the opportunity for behavioral treatment programs to tailor program structures to individual-specific characteristics. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Executive Function and Contingency Management in Methamphetamine Use Disorder.

OBJECTIVES: Contingency management is a promising intervention for Methamphetamine Use Disorder (MUD).Impaired executive function may decrease adherence to such treatment, but there are few data on whether impairment in executive function predicts treatment outcomes. We therefore evaluated whether baseline performance on tests of executive function predicted treatment response in a trial of contingency management for MUD. METHODS: Thirty participants with MUD and 23 healthy controls performed the Connors Continuous Performance Task (CPT) and the Trail Making Task. MUD participants then entered an 8-week contingency management trial. Participants were categorized as responders (n=17; no methamphetamine-positive urine tests) or non-responders (n=13; >1 positive test). The Kruskal-Wallis test was used to compare scores in participants with MUD and healthy controls, and in responders versus non-responders. RESULTS: Participants withMUD performed worse than controls on the CPT (d-prime) (p=0.012); non-responders performed worse than responders (p = 0.034). Performance of MUD participants did not differ significantly from controls on the Trail Making Task B (time to completion), but variation was high with non-responders performing worse than responders (p=0.013). CONCLUSION: These findings suggest that tests of executive function at baseline may be useful in predicting treatment response in MUD. Future work in larger samples may ultimately allow a more personalized treatment approach to methamphetamine use disorder.

Decision-Making by Patients With Methamphetamine Use Disorder Receiving Contingency Management Treatment: Magnitude and Frequency Effects.

BACKGROUND: Individuals with substance use disorders exhibit maladaptive decision-making on the Iowa Gambling Task (IGT), which involves selecting from card decks differing in the magnitudes of rewards, and the frequency and magnitude of losses. We investigated whether baseline IGT performance could predict responses to contingency management (CM) by treatment-seeking individuals with methamphetamine use disorder (MA Use Disorder) in Cape Town, South Africa. METHODS: Twenty-nine individuals with MA Use Disorder underwent an 8-week, escalating reinforcement, voucher-based CM treatment in a study on the suitability of CM therapy for the South African context. Along with 20 healthy control participants, they performed a computerized version of the IGT before starting CM treatment. Seventeen participants maintained abstinence from methamphetamine throughout the trial (full responders), and 12 had an incomplete response (partial responders). Performance on the IGT was scored for magnitude effect (selection of large immediate rewards with high long-term loss) and for frequency effect (preference for frequent rewards and avoidance of frequent losses). Group differences were investigated using linear mixed-effect modeling. RESULTS: Partial responders made more selections from decks providing large, immediate rewards and long-term losses than healthy controls [p = 0.038, g = -0.77 (-1.09: -0.44)]. Full responders showed a greater, nonsignificant preference for frequent rewards and aversion to frequent losses than partial responders [p = 0.054, g = -0.63 (-0.95: -0.29)]. CONCLUSIONS: A predilection for choices based on the size and immediacy of reward may reflect a cognitive strategy that works against CM. Pretesting with a decision-making task, such as the IGT, may help in matching cognitive therapies to clients with MA Use Disorder.

Contingency management treatment for methamphetamine use disorder in South Africa.

INTRODUCTION AND AIMS: As South Africa, especially the Western Cape Province, faces an epidemic of methamphetamine use disorder, therapeutic approaches suited to the South African context are needed. This secondary analysis assessed retention and methamphetamine abstinence outcomes in response to an 8-week pilot contingency management (CM) intervention trial of neural correlates of methamphetamine abstinence, exploring sociodemographic and clinical differences between responders and non-responders. DESIGN AND METHODS: Research participants provided thrice-weekly monitored urine samples, which were analysed by qualitative radioimmunoassay. The primary outcome for this analysis was therapeutic response, defined as abstinence from methamphetamine (≥23 of 24 possible methamphetamine-negative urine samples). RESULTS: Data from 30 adults living in Cape Town, South Africa (34 ± 6.1 years of age, mean age ± SD, 21 men) were included. Sixty-three percent (12 men) were responders. In bivariate comparisons, baseline measurements showed fewer responders reported monthly household income ≥25 000+ South African Rand (ZAR; ~USD $1880; vs. ZAR < 25 000) than non-responders (15.8% vs. 63.6%; P = 0.007). Furthermore, responders had higher median years of education (12 vs. 10; Kruskal-Wallis χ2 = 4.25, DF = 1, P = 0.039) and lower median body mass index than non-responders (19 vs. 24; Kruskal-Wallis χ2 = 6.84, P = 0.008). DISCUSSION AND CONCLUSIONS: Therapeutic response in this study were comparable to those obtained with CM for methamphetamine use disorder in North America and Europe. Our findings suggest that CM may be a useful component of treatment strategies to boost retention and continuous abstinence from methamphetamine in Cape Town, South Africa. Larger efficacy studies are needed in this setting.