Is the treatment long enough? Associations between quality of life and treatment duration in methadone maintenance treatment

Background: Methadone maintenance treatment is currently the mainstream opioid addiction treatment, with proven benefits to quality of life. Aim: Our study aims to determine the right treatment duration to achieve the best quality of life. Methods: This cross-sectional study explored the associations of treatment duration with sociodemographic characteristics, substance-related characteristics, severity of dependence, depression and anxiety, and quality of life among patients with opioid use disorder. We created 5 periods of treatment duration and examined trends using chi-squared tests. Power regression, locally weighted scatterplot smoothing regression analysis, and multivariate regression analysis measured the minimum treatment duration required to achieve the best quality of life. Results: The 200 participants were divided into 5 treatment duration groups (<6 months, 6 months-1 year, 1-2 years, 2-5 years, >5 years). Significant power regressions were found in all domains. Results of the LOESS regression show that scores for all domains of quality of life were lower in participants with a treatment duration shorter than 1-2 years. The curve peaked for participants with a treatment duration in the 1-2-year range. Multivariate regression analysis showed that participants with a treatment period of <1 year have the lowest quality of life; there were no significant differences between the other treatment periods. Conclusions: Participants may need methadone maintenance treatment for at least 1-2 years in order to significantly improve their quality of life and bring it to a stable level.