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An estimated 18.1 percent of Americans suffer from anxiety disorder. Yet, only 36.9 percent currently receive treatment, according to the Anxiety and Depression Association of America.

Women are twice as likely as men to experience anxiety. The condition can cause abnormal fear, depression, or worry. While medications exist for anxiety, some people choose to supplement these with herbs such as St. John’s wort.

St. John’s wort or Hypericum perforatum is a wild-growing plant with yellow flowers. According to the National Institutes of Health, it’s one of the top-selling supplements in the United States. People take the herbal supplement to help with depression, anxiety, or sleeping problems.

Supplement manufacturers make St. John’s wort in different forms, including capsules, tea, or liquid extract.

A lot of the research surrounding St. John’s wort is for its use in treating depression. However, depression and anxiety are closely linked. An estimated 50 percent of people with depression also suffer from some form of anxiety disorder, according to the Anxiety and Depression Association of America.

St. John’s wort is thought to work by keeping the brain from using up neurotransmitters like serotonin, dopamine, GABA, and norepinephrine. As a result, the neurotransmitters are more effectively used in the brain. This can have an antidepressant and overall feel-good effect in the brain. As a result, a person could experience fewer bouts of anxiety.

Anxiety medications, such as benzodiazepines (including Xanax and Ativan), work on GABA transmitters in the brain. Therefore, many researchers believe that St. John’s wort could have anxiety-relieving effects due to its effects on GABA transmitters.

St. John’s wort is perhaps best known in its treatment for mild-to-moderate depression. A 2017 meta-analysis of 27 clinical trials published in the Journal of Affective Disorders concluded that St. John’s wort had a similar level of effectiveness as selective serotonin reuptake inhibitors (SSRIs) in treating mild-to-moderate depression.

The researchers noted the studies were all short-term, ranging from 4- to 12-weeks in length. Therefore, less is known about how effective St. John’s wort is long-term, compared to antidepressant medications. Some people prefer to take St. John’s wort over antidepressants because it typically causes fewer side effects.

Dosages differed between studies. Participants in one study from the National Institutes of Health regarding depression, took an average of 1,300 milligrams of St. John’s wort per day. The highest dose participants took was 1,800 milligrams, while the starting dose was usually 900 milligrams per day, with people taking 300 milligrams 3 times a day.

Unfortunately, there aren’t many long-term human studies related specifically to anxiety and St. John’s wort. A lot of the connections made between St. John’s wort and treating anxiety are because doctors know the effects St. John’s wort has on the brain. Most of these connections, however, are theoretical.

More human studies are needed but a 2017 study on rats showed that St. John’s wort reversed anxiety and depression in rats and improved their response to stress. A 2019 small human study of 48 people, found that taking St. John’s wort helped them respond more positively to negative signals. They also found that St. John’s wort did not change memory function.

A smaller study from 2008 published in the journal Human Psychopharmacology: Clinical and Experimental found that taking St. John’s wort didn’t help reduce anxiety.

The study asked 28 adults with depression and anxiety to take either a placebo or St. John’s wort and the herb kava. At the study’s conclusion, the participants reported improvements in depression symptoms, but not anxiety.

In addition to its use for depression, people use St. John’s wort for other issues, including:

However, the beneficial effects of taking St. John’s wort for these uses are largely rumored. Few have been widely studied.

While several studies and personal reports have found that St. John’s wort can help those with anxiety, it may have the opposite effect in some people.

A case study published in the journal The Primary Care Companion for CNS Disorders reported that a patient who drank a glass of St. John’s wort extract experienced a panic attack shortly afterward. The study noted the report was one of the first to suggest that St. John’s wort could cause a panic attack.

St. John’s wort can cause side effects as well as interact with certain medications. Potential side effects can include:

  • dizziness
  • dry mouth
  • fatigue
  • sensitivity to sunlight
  • stomach upset

Makes some drugs less effective

St. John’s wort also induces the metabolization of certain medications. This means the body breaks them down faster than usual so they may not work as effectively. For this reason, doctors don’t usually recommend taking St. John’s wort if a person takes medications such as:

  • indinavir (used to treat HIV)
  • cyclosporine (used to prevent organ transplant rejection)
  • birth control pills

If you take St. John’s wort (or other supplements), make sure to tell your doctor and pharmacist. Your doctor can make sure St. John’s wort won’t interfere with the medications you take currently.

Serotonin syndrome

If you take St. John’s wort with other medicines that affect neurotransmitter levels, it’s possible you could experience something called serotonin syndrome.

This condition causes symptoms such as agitation, tremors, sweating, and diarrhea. This can happen when you take antidepressants with St. John’s wort. As a result, it’s ESSENTIAL you talk to your doctor about all the medications you’re taking before you try this herb.

In addition, always choose high-quality, regulated products from licensed manufacturers to avoid issues with consistency, strength, and contaminants.

St. John’s wort is likely to help those who suffer from mild-to-moderate depression symptoms. Some people with those symptoms may also have anxiety.

It’s possible that St. John’s wort could reduce anxiety when a person takes it, but researchers haven’t proven this to be true. Discontinue use if you experience an anxiety episode.

Also, if you’re considering trying St. John’s wort, talk with your doctor. They can make sure it won’t interfere with other medications you’re currently taking.