愷他命娛樂性使用之初犯者的再犯率：臺灣2009年至2016年全國性世代的追蹤研究

Recidivism among first-time offenders of ketamine recreational use: a follow-up study of national cohorts from 2009 to 2016 in Taiwan

潘汶萱(Wen-Hsuan Pan)

指導教授 ： 陳為堅

國立臺灣大學/公共衛生學院/流行病學與預防醫學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201903987

摘要

背景及目的
西元2000年代開始，愷他命從普遍於醫療麻醉劑使用，逐漸轉變為被年輕族群於娛樂性使用，特別是在亞洲國家。儘管人們認為愷他命與一般其他非法成癮性藥物相較起來成癮性較低，但其確切之再犯率數據仍然未知。因此，本篇研究主要目的為估計台灣娛樂性使用之愷他命初犯者在2009年至2016年追蹤期間之三年內再犯率，並進一步比較不同性別、年齡、犯罪居住地及初犯時的年代。
方法
台灣於2009年毒品危害防制法修正案修訂攜帶或持有二十公克以下之三、四級毒品（愷他命），須接受行政裁罰，包含限期之內參與四到八小時之毒品危害講習及一萬以上五萬以下之罰鍰。該修正案執行後，犯罪者之犯罪紀錄會記錄於三、四級行政裁罰系統中。本研究利用此資料庫，連結刑事案件紀錄表排除過往有使用過「一、二級毒品」或「攜帶或持有二十公克以上之三、四級毒品」之犯罪者，定義出愷他命初犯者。2009年至2016年之追蹤期間，總共有39178名首次使用愷他命被抓捕到之犯罪者。然而，此篇研究之再犯定義為第二次犯罪紀錄視為再犯，並利用存活分析進行再犯率之分析，其分析策略分為以下三種類型，一為愷他命再犯，其次為升級毒品再犯，最後為任何毒品再犯。本研究進一步執行Cox比例風險模型校正所有的變項，更深入比較在校正年齡、性別、犯罪時居住地、不同初犯年代之下不同組別下之風險比。
結果
愷他命初犯者在初犯一年之後，有四分之一犯罪者使用任何毒品再犯，其三年內再犯率為39.52%。在三種再犯策略分析中，發現男性再犯率高於女性，初犯年紀18至24歲之年輕族群具有較高的再犯率。女性及初犯年紀大於25歲者與其個別對照組比較，具有較低的再犯風險。針對不同年代犯罪者之再犯率比較，2012年愷他命初犯者具有相對高的三年內再犯率。
結論
本研究重要結果為愷他命初犯者在初犯後大約一年之內，有四分之一的犯罪者有任何毒品之再犯情形發生。男性、18至24歲及2012年犯罪者具有較高的三年內再犯率。

關鍵字

愷他命 ； 娛樂性使用 ； 毒品 ； 管制藥品 ； 物質使用 ； 再犯率

並列摘要

Background: Since 2000, ketamine has become a new recreational drug of choice among young people, particularly in Asia. Despite people’s perception that ketamine was less addictive than traditional narcotics, its recidivism remains unknown. This study aims to estimate the three-year recidivism among first-time offenders of ketamine recreational use in national cohorts enrolled from 2009 to 2016 in Taiwan comparing among different sexes, age groups, and locations of offense.
Methods: Persons convicted of possessing or using ketamine of less than 20 grams were stipulated by a law amendment in 2009 to attend a narcotics hazard seminar. Hence these offenders were enrolled in a database called “Administrative Penalty System for Schedule III/IV Illegal Drugs.” Ketamine users with previous drug offense records were excluded after linking with other databases. From 2009 to 2016, a total of 39178 first-time offenders of ketamine use were identified. In the survival analysis for recidivism, an event was defined in three types: 1) repeated drug offense of using ketamine; 2) repeated drug offense of schedule I/ II illicit drugs or possessing schedule III/ IV illicit drugs of over 20 grams; and 3) repeated drug offense of any illicit drug use. Different survival rates were compared using the Log-rank test. The study also provided adjusted hazard ratio of different recidivism analyses by Cox’s proportion hazards model which stratified by sexes, age groups, locational of offense, and year of offense.
Results: The first quantile of time to recidivism was 1.2 years for the recidivism for repeated any drug use, and three-year recidivism probability was 39.52%. In the analysis for three recidivism analyses, the recidivism probability in males was slightly higher than in females (P < 0.0001), and the three-year recidivism probability in people aged 18-24 was also slightly higher than that in people aged over 25 (P < 0.0001). Females and aged groups over 25 years had less risk for three types of recidivism with comparing to their counterparts. With cumulative recidivism probability by years, the cohorts of first-time ketamine offenders in 2012 had higher recidivism probability for up to first to third year for ketamine use (25.09%, 33.96%, 38.82%) and any illicit drug use (28.46%, 38.35%, 43.99%).
Conclusions: Approximately one quarter of first-time ketamine offenders committed recidivism within one years. Males and young adults and cohorts of first-time offenders in 2012 had slightly higher recidivism probability than their counterparts in repeated offense of any drug offense.

並列關鍵字

Ketamine ； recreational use ； illicit drug ； substance use ； recidivism

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