Alcohol, Drugs of Abuse and Road Traffic Accidents A Forensic Toxicology Approach to Medico-Legal Reporting

Abstract

The use of alcohol and psychoactive substances represents a major risk factor for road safety and requires forensic toxicological investigations based on appropriate pre-analytical, analytical and post-analytical procedures. The aim of this study was to assess the frequency of alcohol and/or drug positivity among drivers involved in road traffic accidents in the area served by the Local Health Authority ASL Napoli 3 Sud, and to describe the analytical workflow required for the preparation of a medico-legal report. A descriptive observational study was conducted on 100 blood and/or urine samples received between October 2023 and May 2024 at the Toxicology Unit of ASL Napoli 3 Sud. Samples, collected from several local Emergency Departments, underwent chain-of-custody verification, assessment of matrix suitability, immunoenzymatic screening tests and, in non-negative cases, confirmatory analysis by GC/HS-FID for ethanol and GC/MS for drugs of abuse. Of the 100 cases examined, 66 tested positive, 32 were negative and 2 lacked valid consent. Most subjects were male (70%). The most frequently detected substances were cannabinoids (n = 38), ethanol (n = 30), cocaine (n = 13), opiates/methadone (n = 6) and amphetamines/MDMA (n = 1). Single-substance use was the most prevalent pattern, whereas cannabis–alcohol was the most frequent combination among cases of polydrug use. These findings confirm the relevance of forensic toxicological assessment in road traffic accidents and highlight the need for standardized procedures, appropriate biological matrices and specific confirmatory methods to ensure the evidentiary validity of medico-legal reports.