The Emerging Patterns of New Psychoactive Substance–Related Fatalities in South Korea: A Retrospective Study of Forensic Autopsy Cases

New psychoactive substances (NPS) have rapidly emerged in illicit drug markets worldwide and are increasingly encountered in postmortem examinations. However, postmortem data on NPS-related deaths remain limited worldwide. This study describes postmortem findings from forensic autopsy cases in which NPS were detected and explores the characteristics of these deaths through a retrospective review. Six postmortem cases were identified between 2023 and 2024. The cases predominantly involved young adults. Toxicological analysis identified synthetic cannabinoids, dissociatives, and a stimulant, either alone or in combination with alcohol or conventional illicit drugs such as methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA). Drug paraphernalia or a documented history of drug use was identified in only some cases. The causes of death included acute intoxication and traumatic deaths in which drug intoxication may have contributed to abnormal behavior and fatal outcomes. These findings provide preliminary forensic evidence of the emergence of NPS in South Korea. They underscore the importance of postmortem examination with comprehensive toxicological screening and continued surveillance of emerging psychoactive substances in forensic practice. They also suggest the value of reviewing a history of prior substance use even in unexpected sudden deaths not initially suspected to be drugrelated.