One of the most researched factors which contribute to the good outcome of methadone therapy is the dosage, but local studies which look into the factors associated with the dosage of methadone itself is lacking.

To compare clinical factors including level of motivation and the quality of life among the active male clients on high and low methadone dosage.

To determine the factors associated with high dosage of methadone in order to improve the services provided.

A cross sectional study of active male methadone clients who are on maintenance treatment attending the Methadone Clinic. It was conducted from early January to the end of March 2010. The questionnaires used include Mini International Neuropsychiatric Interview (MINI), Circumstances, Motivation and Readiness to Change (CMR) and WHO-Quality of Life (WHOQOL-BREF).

Those on higher dosages were noted to have significantly better urinalysis results and had a higher CMR score, but quality of life did not differ between the two groups. Motivational level remained significant after regression analysis was done.

This study also confirms previous findings of higher methadone dosage having better outcomes in terms of urinalysis results. As the high dose group were also found to be more motivated to change, the regular formal counselling sessions or motivational enhancement therapy was advocated to improve the services of methadone maintenance therapy.