Zeige- Ringfingerlängenverhältnis und Lateralität als Marker für pränatale Androgenisierung bei problematischem Alkoholkonsum

Background and objective: The consumption of alcohol is widespread in Germany. Alcohol is both a cultural consumable, regulated under food law, and a psychotropic substance that can lead to addiction. Excessive consumption results in physical, mental, and social damage to individuals, as well as societal and economic costs. In this context, the search for risk factors and effective preventive measures is of great importance. Among the many influencing factors, this study investigates the significance of markers for prenatal androgenization in problematic alcohol consumption, including laterality and the length ratio of the index finger (2D) to the ring finger (4D), known as the 2D:4D finger length ratio. Group differences between patients, control participants, and binge drinking participants were examined. The aim of this study is to determine whether the 2D:4D finger length ratio and laterality can be considered markers for problematic alcohol consumption. Method: A total of 98 alcohol-dependent patients were examined. These patients were in early abstinence (24-72 hours of abstinence) and were undergoing inpatient detoxification therapy at the Psychiatric and Psychotherapeutic University Clinic in Erlangen or at the Clinic for Addiction and Psychotherapeutic Medicine at the Klinikum am Europakanal in Erlangen. The control group consisted of 92 healthy control participants and 29 individuals with binge drinking behavior. To measure the 2D:4D finger length ratio, the palms were scanned, and lateralization was assessed using tests for handedness (Shimizu Test), eye dominance, and footedness. Results and observations: The mean and left 2D:4D finger length ratio was significantly smaller in the patient group compared to the control group (mean 2D:4D p = 0.002; left 2D:4D p < 0.001). Participants with binge drinking behavior showed a significantly larger left 2D:4D finger length ratio compared to the patients (p = 0.021). The statistical models for the group differences in lateralization (Shimizu score, footedness, eye dominance, and crossed laterality) did not show any significant correlations with the lateralization markers examined. Conclusion: The data from the study support the findings of previous studies and suggest that intrauterine androgen exposure plays a role in the development of problematic alcohol consumption. As hypothesized, a difference in the 2D:4D finger length ratio was observed between patients and control subjects. Thus, the 2D:4D finger length ratio could serve as an additional, albeit weak, biomarker for identifying patients with alcohol dependence. Contrary to the hypothesis, no significant correlations between the lateralization markers and alcohol dependence were found. Further prospective longitudinal studies are necessary to examine the influence of lateralization on the development of alcohol dependence and to clarify potential causal relationships.