A study into the nature and extent of polydrug use in driving recidivism behavior

Abstract

Objective

Polydrug use has become a frequent pattern of drug consumption in Europe, and this is considered a particularly dangerous risk factor for impaired driving. In Italy, persons whose license has been revoked or suspended due to the use of psychoactive drugs can reapply for a new driving license, depending on the judgment of the relevant local medical committee (CML). To regain a revoked license, offenders must remain drug free throughout an observation period. An important problem with enforcement of impaired driving is recidivism. The aim of the present study is to analyze the influence of polydrug use on driving recidivism.

Method

We report the findings of several years’ experience at the forensic toxicology laboratory of the University of Macerata. Hair samples collected over a 7-year period by the CML from drug users were analyzed for cocaine, opiates, and cannabis using gas chromatography–mass spectrometry.

Results

Three hundred thirty-five of the tested subjects were recidivists. Recidivism was more frequent among monodrug users (81%) compared with polydrug users (19%), but logistic regression showed that polydrug use is certainly a risk factor for recidivism compared to monodrug use (odds ratio [OR] = 1.99). The sex and age distribution of recidivist subjects showed a strong predominance of males in both groups, but there were no sex differences. There were more recidivist polydrug users than recidivist monodrug users in the younger age groups (OR = 2.012). Cocaine use was most prevalent in the recidivist monodrug group. All drugs analyzed were demonstrated to be a risk factor for recidivism among monodrug users, whereas only the cocaine and cannabis combination was shown to be a risk factor for recidivism among polydrug users (OR = 1.65 versus cocaine; OR = 1.30 versus Δ⁹-tetrahydrocannabinol). Almost all polydrug users became monodrug users, and cocaine was the most frequently detected drug in the subsequent test during the monitoring phase.

Conclusions

Our results show that polydrug use increases the risk of impaired driving recidivism and represents a considerable threat to road safety.

Keywords:

• Recidivism
• polydrug use
• hair sample
• impaired driving
• risk factors

Acknowledgments

We thank Jemma Dunnil for proofreading the article. The present work is included in the project “Innovation and Vulnerability. Legal issues and remedies” of the Department of Law, University of Macerata (funded by the Ministry of University and Research Programme, Departments of Excellence 2023-2027).

Disclosure statement

The authors have no conflicts of interest to declare.

Data availability statement

The data used for this article are available on reasonable request to the corresponding author.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.