Kava, also known as kava-kava or kava root, is an herb with numerous bioactives collectively known as kavalactones (including kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin and desmethoxyyangonin).
These bioactives are what researchers believe give this plant its potential medicinal benefits.
Kava has been used in the Pacific Islands for millennia as a ceremonial drink and to promote relaxation.
Kava is effective in treating anxiety. While there are many types of medications available to treat anxiety and depression, many of them come with unwanted side effects and some can be habit-forming. Researchers are searching for safe, effective alternatives.
Mounting evidence shows kava’s efficacy in treating anxiety both on its own and as an adjuvant therapy to traditional medications.
Kava’s effects are reported to be similar to prescription drugs such as benzodiazepines (drugs used to treat anxiety) and buspirone used for the treatment of Generalized Anxiety Disorder (1).
In a study published in Psychopharmacology, researchers found that kava extract was superior to placebo in the Hamilton Anxiety Scale and on the subjective well-being scale. Secondary measures — changes in the Erlanger Anxiety, Tension and Aggression Scale and Clinical Global Impressions — also improved (2).
The duration of the study was five weeks. During the first treatment week, the kava extract dosage was increased from 50 mg to 300 mg per day, while pretreatment with benzodiazepines was tapered off over the course of two weeks. The following three weeks included supplementation of kava extract or placebo.
In a 2009 study, researchers evaluated the effect of aqueous extract of kava with equally promising results. The study was the first documented human clinical trial assessing both its anti-anxiety and antidepressant efficacy.
After three weeks of supplementation consisting of five kava tablets per day containing 250 mg of kavalactones, it was noted that the extract had the ability to significantly reduce symptoms of anxiety and depression.
In addition, there were no adverse effects throughout the duration of the short-term study (3).
A meta-analysis of eleven studies (645 total participants) using kava extracts further supported this plant’s ability to alleviate anxiety. Authors again noted that kava appears to be relatively safe with short-term use (one to 24 weeks) 4.
Kava has the potential to treat insomnia. Insomnia is commonly associated with anxiety, along with other sleep disturbances such as restlessness and tension.
According to the results of a randomized, double-blind clinical study, a daily dose of 200 mg of kava extract resulted in favorable outcomes in helping those with insomnia.
Researchers specifically found an improvement in the following areas: quality of sleep, recuperative effect after sleep, the Hamilton Anxiety Scale and self-rating of well-being (5).
It is believed that kava’s effects on insomnia may stem from its effects in helping alleviate anxiety.
Kava may be a potential mood booster and cognitive enhancer. Using a double-blind randomized placebo-controlled trial, researchers in a recent study evaluated mood changes and cognitive performance in a group of healthy volunteers.
Researchers relied on the state-trait-cheerfulness-inventory (which measures the three concepts of cheerfulness, seriousness and bad mood) for reports of mood changes and used the Sternberg item recognition task (which is used as an index for visual attention and short-term memory processing) to evaluate cognition.
Results showed that a single oral dose of 300 mg of kava extract led to an increased state of cheerfulness and improved visual attention and short-term memory retrieval (6).
In a word recollection test, extract of kava root improved performance and acute recollection (7).
Kava has an anticonvulsant effect. In 2013, researchers set out to evaluate the anticonvulsant effect of kava when used alone or in combination with the anticonvulsant drug, diazepam.
Using a rat study, results revealed that kava increased the maximal electroshock seizure threshold and enhanced the anticonvulsant effect of diazepam following both acute and chronic treatment.
In addition, neither kava nor its combination with diazepam impaired motor co-ordination (8).
Kava exhibits neuroprotective ability. In a study using mice and rats with induced ischemic brain damage, researchers found that kava extract and some of its bioactives exhibited neuroprotective activity.
The effects of the kava extract and its constituents were compared with those produced by the typical anticonvulsant drug, memantine (9).
Research is underway to also evaluate kava’s pain-relieving and muscle relaxing properties.
While several human trials performed using kava have not resulted in significant adverse effects, it is important to note that supplementation was only used for a short time period (most have been shorter than two months).
Side effects including headache, impaired reflexes, sedation, restlessness, tremor and a hangover-like effect have been reported (10).
There is great concern that use of kava causes liver toxicity.
Multiple cases of hepatitis, cirrhosis, and liver failure have been reported in Europe. As a result, it has been taken off the market in some countries, including several European countries, Australia and Canada (11).
In the U.S., the FDA has issued warnings to consumers and physicians regarding safety concerns with kava use.
Long-term use and high dosages have also been linked to neurotoxicity, pulmonary hypertension and skin changes (flaky, dry, scaly skin and discoloration of the skin, hair and nails) 12.
Kava may also interact with some other drugs.
According to the World Health Organization’s Assessment of the Risk of Hepatotoxicity with Kava Products, it is not yet clear why kava causes liver toxicity; researchers are seeking to learn whether dose, variety of kava, plant parts used or type of extract (or a combination) is the cause of toxicity and liver damage (13).
Due to serious safety concerns such as liver damage and toxicity, it is highly recommended that anyone considering taking supplementation first seek the advice of a medical professional.
Kava is an herbal supplement that has been taken for hundreds of years in the Pacific Islands for its sedative and anxiety reducing effects.
Kava is also being studied for its cognitive, mood-enhancing and anticonvulsant effects, neuroprotective ability and for its ability to treat insomnia.
While research supports its anti-anxiety effect, there is great concern regarding serious side effects that come with prolonged use, such as liver damage and toxicity.
Before considering taking kava, it is best to first consult with a physician.