Psychiatric comorbidity among patients on methadone maintenance therapy and its influence on quality of life.

BACKGROUND AND OBJECTIVES: Co-occurring psychiatric disorders are among the difficulties faced by patients with opioid dependence on methadone maintenance therapy (MMT). This study aims to assess the prevalence of psychiatric comorbidity among patients on MMT, the factors predicting psychiatric comorbidity and to examine the association between psychiatric comorbidity and quality of life. METHODS: A total of 225 male patients on MMT in a tertiary hospital in Malaysia were assessed for psychiatric comorbidity and substance use disorders using the Mini-International Neuropsychiatric Interview (MINI) and Opiate Treatment Index (OTI). Their quality of life was assessed using World Health Organization Quality of Life (WHOQOL)-BREF. RESULTS: The prevalence of a current and lifetime non-substance use Axis I psychiatric disorder was 14.2% and 15.6% respectively, while 14.7% fulfilled the criteria for antisocial personality disorder. 80.9% had comorbid substance dependence, predominantly nicotine dependence. Factors significantly associated with a non-substance use Axis I psychiatric disorder on multivariate analysis were use of psychiatric medications, antisocial personality disorder and poorer physical health. Patients with a non-substance use Axis I psychiatric disorder had a significantly poorer quality of life in all domains namely physical health, psychological, social relationships, environment as well as combined quality of life and general health after controlling for possible confounders. CONCLUSION: Psychiatric comorbidity among patients on MMT negatively impacts quality of life. SCIENTIFIC SIGNIFICANCE: The detection of psychiatric disorders and provision of appropriate treatment is needed to improve the quality of life of patients on MMT.

Effectiveness of Methadone Maintenance Therapy and Improvement in Quality of Life Following a Decade of Implementation.

Methadone maintenance therapy has been found to be an effective harm reduction treatment for opioid use disorder. However evidence of its benefits over a longer duration of treatment is limited as most studies focus on its short term benefits. As methadone maintenance therapy reaches a decade since its implementation in Malaysia, this study sought to examine the effectiveness of methadone treatment, change in quality of life among patients since entry to methadone treatment, as well as factors predicting the magnitude of change in quality of life. This study found that methadone maintenance therapy was effective in reducing heroin use, injecting practices and crime, and in improving in social functioning and physical symptoms, but not in reducing sex-related HIV risk-taking behavior. Though patients had a significantly better quality of life at follow-up than at entry to methadone maintenance therapy, the improvement in quality of life was not significantly greater as the duration of treatment increased. Age above 50 years old, human immunodeficiency virus (HIV) positive status and physical symptoms predicted a poorer improvement in quality of life between baseline and follow-up. On the other hand, patients with hepatitis B showed a greater improvement in quality of life in the social relationships domain compared to patients without hepatitis B. In conclusion, methadone maintenance therapy is an effective treatment for opioid use disorder and improves quality of life but its benefits in further improving quality of life beyond a decade of treatment need further evaluation.