海洛因是台灣最常見的成癮藥物，而美沙冬維持治療則是戒治海洛因成癮的主要療法。本研究欲檢驗工作記憶廣度對海洛因／美沙冬雙歷程模式（即外顯態度與內隱態度）在美沙冬維持治療流失風險的調節作用，並預測接受美沙冬維持治療的海洛因成癮者在未來3個月內的流失風險。研究對象為62位接受美沙冬維持治療的海洛因成癮者。研究採用電腦版的單軸單一類別內隱連結測驗（Unipolar Single Category Implicit Association Test）測量參與者對海洛因與美沙冬的正負向內隱態度，以對稱廣度作業測量工作記憶廣度。最後再以自陳問卷測量海洛因及美沙冬的外顯態度，並追蹤實驗後3個月內的美沙冬維持治療出席情形。從生存分析的Cox比例風險模型之分析結果顯示，工作記憶廣度與美沙冬負向內隱態度的交互作用能顯著預測未來3個月內的美沙冬維持治療流失風險。其中，對低工作記憶廣度者而言，美沙冬負向內隱態度能預測未來3個月內的流失風險；也就是當美沙冬負向內隱態度越強時，流失的風險越高。此發現有助於發展新的美沙冬維持治療風險預測模型，以提早辨識出容易流失的高風險族群。
Heroin is the most common addictive drug in Taiwan, and methadone maintenance treatment (MMT) is the primary intervention that has demonstrated effectiveness and advantages on heroin dependence. We investigated whether the mederation of working memory capacity (WMC) on interplay between explicit and implicit heroin/methadone attitudes can predict the hazard ratio of discharge from methadone maintenance treatment (MMT) in patients undergoing MMT during the 3 month follow-up. Sixty-two heroin users in MMT participated in the current study. Implicit heroin and methadone attitude were assessed by computer-based version of the Unipolar Single Category Implicit Association Test (Unipolar SC-IAT). WMC was assessed by computer-based version of the Symmetry span task (SST). Finally, explicit heroin and methadone attitudes were assessed by the questionnaires. A survival analysis using a robust estimation for the Cox PH regression showed that the interaction between methadone negative implicit attitude and WMC predicted unique variance in the risk of dropping out from MMT during the 3 month follow-up. For the low-WMC participants, strongly methadone negative implicit attitude may increase the risk of dropping out of MMT during 3 month follow-up. This discovery will help us to develop a new model to predict and identify the high-risk group in MMT.
