[The randomized controlled trial of the prison-based Japanese Matrix Program (J-MAT) for methamphetamine abusers]

Abstract

Methamphetamine use is subject to severe criminal punishment in Japan and approximately 22% of the prison population were confined for violations of the stimulants control law in 2009. Although the high recidivism rate is also a problem, no systematic treatment has been conducted in prison. Therefore, the development of the prison-based treatment program is necessary. In this study, the prison-based program was developed based on the Matrix Model, which is the cognitive-behavioral treatment for amphetamine users developed in the US. The program was tailored in order to address the treatment needs of the Japanese amphetamine users considering Japanese culture and the prison climate. The randomized controlled trial was conducted in order to evaluate the effectiveness the Japanese Matrix program (J-MAT). 60 prisoners were randomly assigned either to the J-MAT or the control groups and those who in the J-MAT group received the program once a week for 12 weeks. The abstinence rate could not be used as the outcome measure because the participants could not be followed after the release from prison due to the legal reasons. Therefore, the psychological variables including coping skills, self-efficacy and motivation were used as outcome measures, which are considered as the important predictive factors of abstinence. 93.3% of the J-MAT participants completed the program. The coping skills of the treated prisoners were improved significantly after treatment comparing to the control (F (1, 27) = 9.03, p < .001), however other psychological variables were not significantly improved. The results suggested the effectiveness of the J-MAT because both treatment completion and coping skills are powerful predictors of abstinence. Further study is required and in which the participants should be followed after the completion of treatment in order to compare the relapse rates between the groups and to measure the long-term treatment gain.