Police and Security, Vol. 34 No. 3, 2025.
Original scientific paper
https://doi.org/10.59245/ps.34.3.2
The Influence of Alcohol on Participants’ Breath, Blood, and Handwriting
Andrea Ledić
orcid.org/0000-0003-1396-8240
; Forensic Science Centre Ivan Vučetić, Zagreb, Republic of Croatia.
Abstract
Writing is a complex cognitive-motor activity that requires the synchronised functioning of multiple neurological systems, including the frontal, parietal, and temporal lobes of the brain, which manage movement planning, spatial orientation, and visual processing (Garnacho-Castaño et al., 2020). The precision of handwriting features can be subject to variations due to various factors, including emotional state, fatigue, illness, or pharmacological influences such as alcohol. One of the key internal factors that can significantly impact handwriting is alcohol consumption. Alcohol acts as a central nervous system depressant, primarily through the enhanced activation of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which leads to reduced motor control and slower reflexes (Caligiuri & Linton, 2012). As alcohol levels increase, inhibition spreads to the cerebellum, crucial for precise movement control, resulting in changes in handwriting, including unstable lines, tremors, variations in the slant of letters, and reduced consistency in character size (Asicioglu & Turan, 2003).
Although previous studies have indicated changes in handwriting under the influence of alcohol, most of them relied on qualitative analysis methods. This study aims to quantify handwriting changes through an interdisciplinary approach that combines toxicological analysis and forensic handwriting analysis. By using gas chromatography with flame ionisation detection (HS-GC-FID) to determine alcohol concentrations in biological samples and analysing handwriting features at various levels of intoxication, the research will enable more precise identification of characteristic handwriting changes. The results of this study may have significant implications for forensic handwriting examination, legal practice, and traffic safety. By improving handwriting analysis methods in the context of intoxication, it is possible to enhance the processes of identifying document authors, which could play an important role in court proceedings and criminal investigations.
Keywords
forensic handwriting analysis; toxicological analysis; alcohol.
Hrčak ID:
334199
URI
Publication date:
23.9.2025.
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