It is always a good idea to keep an eye on your drink when out at night. However, the first national review of Danish drugging cases in which no sexual assault occurred shows that many episodes can probably be explained by alcohol alone.
The review is based on an examination of all cases submitted for forensic toxicological analysis at the three Danish departments of forensic medicine in Copenhagen, Odense, and Aarhus between April 2022 and June 2024. In total, this includes 373 incidents in which primarily young women experienced unpleasant symptoms and suspected they had been drugged.
The researchers found that alcohol was the most frequent finding in the complainants’ blood and urine samples. It was detected in 48% of cases.
At the same time, blackout was the most commonly reported symptom — a well-known phenomenon associated with high alcohol intake.
“We often find alcohol, and in a number of cases the blood alcohol concentration is so high that it likely explains the symptoms experienced, including blackout,” says senior researcher Jørgen Bo Hasselstrøm from the Department of Forensic Medicine at Aarhus University.
Alcohol is an intoxicant that should be taken seriously
“People sometimes forget how alcohol can affect them,” the senior researcher says.
In 65% of the 373 urine and blood samples, at least one legal or illegal substance was found in the body. Most often, this was alcohol. Although samples were taken on average 18 hours after the unpleasant incident — when alcohol in some cases had already been eliminated from the body — nearly one in five still had a blood alcohol level above 1.0 permille, and one in ten above 1.5 permille.
On average, women reach a higher blood alcohol level than men after consuming the same amount of alcohol. A woman of normal weight can reach a blood alcohol level of 1.5 permille after quickly consuming five drinks, which may cause blurred vision and speech as well as impaired consciousness.
The results therefore support the Danish Health Authority’s recommendation of no more than four drinks on the same day.
Only a few cases can be classified as actual drugging
In 11% of cases, central nervous system stimulants were found; in 9%, antidepressants; and in 7%, cannabis. Sedative substances such as benzodiazepines and opioids — which are often associated with drugging — were found in fewer than 5% of cases.
In 82 of the 373 police reports, the victims had stated their own intake of alcohol, medication, and illegal substances. In one quarter of this group, researchers found illegal drugs or medications that the person had not reported to the police. If the individuals’ statements are accurate, they have been subjected to drugging, explains Jørgen Bo Hasselstrøm.
One in ten in this group had sedative medications such as opioids and benzodiazepines in their test results. These types of substances are often associated with drugging because they can quickly impair a person and make them less able to resist or remember what happens.
“Drugging does occur, and it can have serious physical and psychological consequences. But the results suggest that fortunately it does not seem to be as frequent as often as many people might think,” the senior researcher says.
You are more vulnerable when you have been drinking
It is still sensible to keep an eye on your drink, Jørgen Bo Hasselstrøm emphasizes.
“The effects of sedative substances are enhanced by alcohol. And you may be more vulnerable to other substances if you have been drinking,” he says.
He also points out that the effects of legal medications such as antidepressants and ADHD medication can be intensified when combined with alcohol.
“Finally, we should not forget that drugging can also occur with alcohol — for example, if your drink is much stronger than you expect,” he says.
The study has methodological limitations, including the time delay between the incident and sampling, as well as missing information about self-reported intake in many cases.
“Nevertheless, the study provides important data to nuance the debate about drugging. At the same time, it reminds us that alcohol can be far more risky than many people imagine,” says Jørgen Bo Hasselstrøm.
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What does the study show?
About the research findings
Contact
Senior Researcher Jørgen Bo Hasselstrøm
Aarhus University, Department of Forensic Medicine
Phone: +45 51 24 61 12
Email: jbha@forens.au.dk
Forensic Toxicology
Data/statistical analysis
People
Toxicological findings in suspected drugging incidents in Denmark from 2022 - 2024
15-Dec-2025