First-time offenders for recreational ketamine use under a new penalty system in Taiwan: incidence, recidivism and mortality in national cohorts from 2009 to 2017

Wen-Hsuan Pan; Kevin Chien-Chang Wu; Chi-Ya Chen; Yu-Roo Chu; Shang-Chi Wu; Susyan Jou; Tzu-Pin Lu; Yu-Chi Tung; Jui Hsu; Wei J Chen

doi:10.1111/add.15337

First-time offenders for recreational ketamine use under a new penalty system in Taiwan: incidence, recidivism and mortality in national cohorts from 2009 to 2017

Addiction. 2021 Jul;116(7):1770-1781. doi: 10.1111/add.15337. Epub 2020 Dec 20.

Authors

Wen-Hsuan Pan¹, Kevin Chien-Chang Wu^{2

3}, Chi-Ya Chen¹, Yu-Roo Chu⁴, Shang-Chi Wu¹, Susyan Jou⁵, Tzu-Pin Lu^{1

6}, Yu-Chi Tung^{6

7}, Jui Hsu⁴, Wei J Chen^{1

2

6

8}

Affiliations

¹ Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
² Department of Psychiatry, College of Medicine and National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan.
³ Department of Medical Education and Bioethics, College of Medicine, National Taiwan University, Taipei, Taiwan.
⁴ Division of Controlled Drugs, Taiwan Food and Drug Administration, Ministry of Health and Welfare, Executive Yuan, Taipei, Taiwan.
⁵ Graduate School of Criminology, National Taipei University, New Taipei, Taiwan.
⁶ Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan.
⁷ Institute of Health Policy and Management, College of Public Health, National Taiwan University, Taipei, Taiwan.
⁸ Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan.

PMID: 33197101
DOI: 10.1111/add.15337

Abstract

Background and aims: Ketamine has become a new recreational drug of choice among young people in parts of Asia. Using national databases in Taiwan, this study aimed to (1) examine the yearly trend in the ketamine offence rate over time; (2) estimate the 3-year risk of drug-related re-offence and its correlates among the first-time offenders; and (3) estimate the 3-year standardized mortality ratio (SMR) among the first-time offenders.

Design, setting and participants: Retrospective cohort studies of offenders for recreational ketamine use in a penalty system initiated in 2009. Offenders for recreational ketamine use were identified from the Administrative Penalty System for Schedule III/IV Substances database from 2009 to 2017, and the re-offence rate and mortality among first-time offenders were assessed via record-linkage within the database as well as with both the criminal drug offence database and the national mortality database. The cohort from 2009 to 2016 (n = 39 178) was used for the recidivism analysis and the cohort from 2009 to 2013 (n = 25 357) was used for the 3-year SMR analysis.

Measurements: Recidivism was estimated using survival analysis of the event as re-arrest for using ketamine, more serious illicit drugs (Schedules I/II), or any illicit drugs (ketamine or Schedules I/II). SMRs were estimated for overall and cause-specific death within 3 years after the first offence for ketamine use.

Findings: The age-standardized rates for both prevalent (1.38 per 1000) and first-time offenders (0.65 per 1000) peaked in 2013 and then decreased steadily. The 3-year risk of re-offence was 33.85% [95% confidence interval (CI) = 33.23-34.47%) for ketamine use and 39.52% (95% CI = 39.00-40.04%) for any illicit drug use. These first-time offenders had an SMR of 4.9 (95% CI = 4.3-5.4) for overall mortality, 2.1 (95% CI = 1.6-2.7) for natural deaths and 7.6 (95% CI = 6.7-8.6) for unnatural deaths.

Conclusions: Recreational ketamine use in Taiwan appears to lead not only to high risk for drug-related re-offence but also to excess mortality.

Keywords: Ketamine; illicit drug; recidivism; recreational use; standardized mortality ratio; unnatural death.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Criminals*
Humans
Incidence
Ketamine*
Recidivism*
Retrospective Studies
Taiwan / epidemiology

Substances

Ketamine