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Taking Passion Flower for Anxiety: How Effective Is It?

Sally-Anne Soameson, Psychiatrist
Taking Passion Flower for Anxiety: How Effective Is It?

The species of passion flower Passiflora incarnata, or “maypop,” as it is also known, is a plant with a wide variety of medicinal properties. Thought to be useful in treating everything from insomnia to asthma to narcotic withdrawal, it was originally used primarily to treat the conditions of “restlessness” and “hysteria,” which in the modern day translates to anxiety.

This article will examine the history of passion flower as an anxiety treatment, its potential medicinal properties, and the results of studies measuring its effectiveness in rodents and humans against other anxiety medications.

History of Passion Flower as Treatment for Anxiety

People have long wanted natural ways to treat anxiety because medications are believed to have a lot of side effects. But the truth is that even natural medicines can have side effects, and even if they don't, psychologists do not advise using only a medicinal treatment. 

Indigenous Americans are the first people known in history to have found a use for Passiflora incarnata, a flowering vine thought to have originated in the Western hemisphere. The leaves, flowers and even the fruit of Passiflora incarnata were all thought to be useful (though the roots were not noted as having any special properties).

Settlers in the Americas were responsible for spreading the use of passion flower as a sedative across the world when they learned from local residents of its various medical uses. The Spanish renamed it the “passion flower” due to its striking appearance, which they assigned symbolic meanings relating to the passion of Christ. The spiky looking ring around the flower’s center paralleled the crown of thorns, and the ten white petals symbolized the ten faithful apostles, excluding Judas and St. Peter.

Marketed as a sleep aid and mild sedative in the U.S. in the year 1978, it was taken off the market due to a lack of proof of its effectiveness. Since then, trials have been performed that seem to indicate that it is, in fact, a viable alternative to typical anti-anxiety meds, and passion flower is once again available without a prescription in most supplement stores, as well as online.

How Passion Flower Works

Within the medical community, the jury is still out on exactly how passion flower works, though various studies have shown it to be effective in cases of anxiety, which be discussed further in the following section.

The components of plant based medicines that affect the body are collectively called “flavonoids.” Passion flower contains many flavonoids. Some evidence suggests that the flavonoids “chrysin” and “benzoflavone” may be the primary flavonoids in passion flower that are responsible for decreasing anxiety.

Chrysin and benzoflavone are believed to have the effect of increasing the amount of gamma-aminobutyric acid (often abbreviated as GABA) in the brain, much in the same way that standard anti-anxiety meds known as “benzodiazepines” do. GABA limits the “excitability” or reactivity of the brain’s neurons. This results in the calming effect that gives passion flower its reputation as a mild sedative but means that it can also disrupt mental and motor functions in higher quantities.

Studies of Passion Flower’s Effectiveness

In a study from the Universite de Metz in France, it was suggested that the flavonoids contained in passion flower were responsible for decreasing anxiety symptoms in mice that had been dosed with addictive substances and then subjected to a period of withdrawal. In another study using rats, prolonged sleeping time and lowered levels of activity were noted as significant behavioral changes.

In a trial comparing the effectiveness of passion flower to that of the scientifically accepted anti-anxiety medication oxazepam, a dosage of 45 drops per day of extract of passion flower was found to be as effective as 30 mg per day of oxazepam over a period of four weeks, with fewer short term side effects. Though long term studies were recommended as a follow up to ensure passion flower’s safety, such studies have yet to be performed on humans.

Alkaloids belonging to a potentially toxic alkaloid subgroup known as “harmala” have been found in passion flower in trace amounts. This suggests that taking too much passion flower or taking it for too long could potentially be harmful, and underlines the importance of performing long term studies.

Additionally, though this article has focused on the specific species also known as Passiflora incarnata or the “maypop” flower, it is important not to confuse this species of passion flower with Passiflora alata. Taking the extract of this type of passion flower is known to have a genotoxic effect on the body’s cells. Genotoxic substances damage the genetic information within the cells, which can lead to mutations and potentially cause cancer.

When Not to Take Passionflower

Due to some of the active chemicals in passion flower, it is recommended that this supplement NOT be taken for anxiety in the following situations:

For optimal effects and to avoid putting yourself in danger, take passion flower only in moderation and when you are not expecting to become pregnant, have surgery, or need to take another type of sedative.

Should You Use Passion Flower for Anxiety?

While passion flower is believed to be effective in the short term, its long term effects have yet to be established, and very few controlled studies have shown any substantial results. There is a chance that passion flower's effect on anxiety is either very mild or a placebo, but many people do use it today with varying degrees of success.

If you do intend to use passion flower as a treatment for your anxiety, pay attention to the dosage to avoid any harmful effects from the harmala alkaloids. Also, bear in mind that your motor skills may be impaired by higher doses. Dizziness, confusion and lack of muscle coordination have been noted as possible side effects.

According to the studies that have been done there is little known risk to taking extract of Passiflora incarnata, and the supplement can be effective, but it is acknowledged within the scientific community that further studies are needed.

Article Resources
  1. Akhondzadeh, Shahin, et al. Passionflower in the treatment of generalized anxiety: a pilot double‐blind, randomized controlled trial with oxazepam. Journal of Clinical Pharmacy and Therapeutics 26.5 (2001): 363-367.
  2. Miyasaka, L. S., A. N. Atallah, and B. G. Soares. Passiflora for anxiety disorder. Cochrane Database Syst Rev 1 (2007).
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