What are the negative side effects of absinthe?

Dear Reader,

As an herb-infused alcoholic beverage, absinthe was euphemistically referred to as the “Green Fairy” due to its emerald color. Absinthe is derived from anise, fennel, and the leaves and flowers of  a plant called Artemisia absinthium — more commonly known as wormwood — which grows in small shrubs and is recognizable by its pale flowers and small, silvery leaves. Absinthe typically has an alcohol content of 45 to 74 percent and it's often mixed with other alcoholic drinks or, as it was served to you, with water. Given its high alcoholic content, it's likely that any effects you felt from consuming it were due to the alcohol, rather than the thujone (more details on thujone coming!) and it's unlikely that you would experience any lingering effects from just one shot. When it comes to your concerns around how absinthe use may affect mental health, it's understandable how the suicide of your acquaintance has you rattled. That being said, it's likely that the cause of your acquaintance's suicide is much more complex than simply drinking absinthe. While many people use substances (be it alcohol or others) as a coping mechanism, there isn't any research to indicate that absinthe use itself contributes to death by suicide. As you cope with the loss of your acquaintance, you may also find it useful to seek out additional support through a friend, family member, or mental health professional. Grief can manifest in many ways, whether you knew the person well or not. 

As far as your questions about negative side effects, absinthe has mystified researchers since it first rose to prominence in Europe. People who drank it frequently began hallucinating, having seizures, experiencing vision impairment, and having cognitive troubles. At that time, "absinthism" (an addiction to absinthe) was blamed for causing psychosis and encouraging criminal behavior in those who drank the libation. As a result of this negative reputation, the beverage was banned in many countries at the beginning of the 20th century including Switzerland, France, and the United States; however, by the late 1990s, the historic claims about absinthe’s drastic effects on the body and mind had been disproven. 

You mentioned that the absinthe you drank contained 100 milligrams (mg) of thujone. Thujone is the principal active ingredient in wormwood oil, but thujone-free wormwood oil exists. In fact, beverages in the United States must be legally thujone-free. Thujone is considered to be a neurotoxin and has been known to slow reaction times and impair a person’s ability to pay attention. It also may cause visual or auditory hallucinations for some people. That being said, more recent research suggests that absinthe (which contains wormwood oil) has a high alcohol concentration, which may be a more likely culprit for the purported side effects than solely thujone. It would follow then that your single drink is unlikely to result in any lasting adverse effects. Possession and sale of thujone-free absinthe is legal in the U.S. with a number of regulations in place to promote safety. For example, a product can only be labeled as “absinthe” if it is legally thujone-free (meaning that it contains less than ten parts per million of thujone). American producers and importers of absinthe are also required to submit samples to the Beverage Alcohol Laboratory to test for the presence of thujone.

While electronic commerce has made it possible to obtain absinthe containing thujone from countries such as the Czech Republic, absinthe in the European Union (EU) can contain no more than 35 mg of thujone per liter. The 100 mg label you saw may have been a marketing tactic to try and sell absinthe to those who are looking for higher levels of thujone. Furthermore, it’s possible that the amount of thujone you had was even lower than that — analyses of thujone content in absinthe have shown that many don’t exceed two mg per liter.

Currently, there’s not a whole lot of ongoing research on absinthe because it's no longer as widely consumed. It's known, however, that since the beverage has a high concentration of alcohol, it’s difficult to separate the effects of thujone from the standard effects of alcohol. Many of the problems that were historically attributed to absinthe — irresponsible or erratic behavior, withdrawal, dependence, and serious health problems such as brain damage — may have been due to acute alcohol intoxication or overconsumption of alcohol rather than the thujone itself. Similar to other drugs, each person's body will respond differently. Excessive use of any kind of alcohol can result in significant health problems. If you need additional support, whether you're examining your relationship with substances or your experiences with loss, you may find the support of a mental health professional or substance use counselor to be supportive during this time. 

Hope this information eases some of your worries.