Cognitive improvement among abstinent methamphetamine users: A 2-year prospective longitudinal study

Background and Objectives The adverse impact of chronic methamphetamine (MA) use on cognitive function has been described in previous studies, but limited evidence is available for abstinent users from prospective longitudinal studies. The aim of the present study was to assess cognitive function of varying abstinent duration. Methods This prospective longitudinal study was conducted with baseline and four follow-up interviews every 6 months over 2 years in 358 MA users in Guangdong province, China. The Montreal Cognitive Assessment (MoCA) was used to measure cognitive function. Generalized estimating equation (GEE) analysis was used to examine within-subjects relationships between abstinence and cognitive consequences over time. Results The repeated measure analysis of variance showed significant differences in the total MoCA score and all subscale scores (except Orientation) in the 24 months follow-up. The GEE model showed that abstinence from MA in the past 6 months predicted an increase of 0.66 (95% confidence interval [CI] = 0.29 to 1.05, p = .002) in MoCA score changes compared with the nonabstinence MA users. Abstinence in the past 12, 18, and 24 months predicted an increase in MoCA total score changes of 1.25 (95% CI = -0.23 to 2.74), 2.15 (95% CI = -0.79 to 5.09), and 5.28 (95% CI = -2.01 to 12.58), respectively, but none of these was statistically significant. Discussion and Conclusions Cognitive function was potentially improved following 6 months of MA abstinence. Scientific Significance This study extends prior research by long-term follow-up in big sample MA abstinence users. Findings from study support the need for a comprehensive measure to decrease MA use and promote the recovery of cognitive impairment.