(Vienna, 06-08-2026) A study conducted at the Medical University of Vienna on the effects of vitamin B1 (thiamine) on memory performance in people with alcohol dependence has been included in the latest World Health Organization (WHO) guidelines on risk reduction of cognitive decline and dementia. The recently published guidelines incorporate the findings of the MedUni Vienna study into their recommendations for the care of people with alcohol dependence.
Excessive alcohol consumption is considered a major modifiable risk factor for cognitive impairment. As demonstrated in a study published in 2023 by the research team led by Stephan Listabarth and Daniel König-Castillo from the Clinical Division of Social Psychiatry at the Department of Psychiatry and Psychotherapy, Medical University of Vienna, part of this risk is associated with vitamin B1 (thiamine) deficiency. Targeted thiamine supplementation may, however, at least partly prevent or improve cognitive decline.
To obtain these findings, the researchers examined 50 patients undergoing inpatient alcohol withdrawal treatment. All participants received thiamine, either intravenously followed by oral tablets or exclusively in oral form. The researchers repeatedly measured blood concentrations of thiamine pyrophosphate, the biologically active form of thiamine, and assessed cognitive performance. Of particular relevance was the association with delayed memory recall: in an exploratory analysis, the greater the increase in thiamine levels, the greater the improvement in this cognitive domain. This association remained significant even after adjusting for alcohol consumption, depressive symptoms and baseline memory performance.
The study opens up an important clinical perspective: alcohol-related cognitive decline may not necessarily be inevitable or entirely permanent in every case. If thiamine deficiency contributes to cognitive impairment, timely supplementation may help prevent deficits or partially restore certain memory functions. The new WHO guideline explicitly cites the MedUni Vienna study as evidence that thiamine supplementation may improve cognitive function in people with alcohol dependence. Its implementation considerations specifically recommend including nutritional support – such as thiamine supplementation – in treatment protocols to promote cognitive function.
The message for clinical practice is therefore clear: in people with hazardous alcohol use or alcohol dependence, clinicians should not wait until severe neurological symptoms develop. Early medical assessment, evidence-based treatment of alcohol dependence and appropriately administered thiamine supplementation can together help prevent avoidable brain damage and support cognitive function. However, self-administered high-dose thiamine is not a substitute for medical diagnosis and treatment.
The WHO guidelines Risk reduction of cognitive decline and dementia summarize the current state of evidence on interventions that may help preserve cognitive health and reduce the risk of cognitive decline and dementia. These evidence-based recommendations are intended for health systems, policymakers and healthcare professionals worldwide and carry considerable weight in clinical practice because of the WHO's international authority. "The inclusion of our study in these guidelines demonstrates the international impact of research conducted at MedUni Vienna," says first author Stephan Listabarth.
Publication: Alcohol and Alcoholism
Can thiamine substitution restore cognitive function in alcohol use disorder?
Stephan Listabarth, Benjamin Vyssoki, Rodrig Marculescu, Andreas Gleiss, Magdalena Groemer, Armin Trojer, Christine Harrer, Sabine Weber, Daniel König
https://doi.org/10.1093/alcalc/agad017
WHO-Guidelines: „Risk reduction of cognitive decline and dementia“