St. John's wort (also known as Perforate St. John's wart, Tipton's Weed or Klamath weed) is a medication that comes from a flowering plant called Hypericum perforatum. For a long time it has been believed to have medicinal qualities, especially for the treatment of depression. Recent studies appear to conclude more favorably than unfavorably regarding St. John's Wort's efficacy in treating depression.
Studies from reputable research centers report that St. John's wort is more effective than a placebo and equally effective as tricyclic antidepressant drugs in the short-term (1 to 3 months) treatment of mild-to-moderate major depression. Experts continue to debate whether St. John's wort is as effective as SSRIs (selective serotonin reuptake inhibitors).
Experts say that the active chemical in St. John's wort - hypercin - is probably what gives the herb most of its efficacy. The herb also has other chemicals which may play a role.
Some herbal medications, including St. John's Wort, can clash with prescription drugs in a dangerous way, researchers from the College of Pharmacy, China Medical School, Taiwan, reported in the International Journal of Clinical Practice in October 2012.
In addition to this, some people taking St. John's wort may experience photosensitivity (sun sensitivity), stomach upset and allergic reactions. We review the possible side effects and risks associated with St. John's Wort later in this article.
Cochrane review of St John's Wort
A report in the Cochrane Review in 2008 looked at available evidence and suggested that the hypericum extracts tested in the reviewed trials:
- were superior to placebo in patients with major depression
- were similarly effective as standard antidepressants
- had fewer side effects than standard antidepressants.
However, the review also mentioned two issues which complicated the interpretation of their findings:
- While the influence of precision on study results in placebo-controlled trials was less pronounced in this updated version of their review compared to the previous version (Linde 2005a), results from more precise trials still show smaller effects over placebo than less precise trials.
- Results from German-language countries are considerably more favorable for hypericum than trials from other countries.
Why the name "St. John's"?
St. John's Wort is named after St. John the Baptist, whose feast day (24th June) occurs when the plant is in full bloom. Red spots are said to appear on the plant's leaves on August 29th in the northern hemisphere - the anniversary of the death of John the Baptist (St. John), representing the blood spilt when he was beheaded. Some say the herb was used to treat the wounded in the crusades by the Knights of St. John.
St. John's wort has been used for hundreds of years in folk medicine, especially for the healing of wounds. It was used for "driving out the inner devil" in medieval times. Paracelcus (c1525), a philosopher, recommended the herb for hallucinations and dragons, as well as for healing wounds.
In 1959 and 1971 St. John's wort's antibacterial properties were scientifically reported - its antibacterial substance, hyperforin was extracted and analyzed.
Medical use of St. John's wort
St. John's wort is widely used in Europe, especially Germany, as an herbal treatment for depression. Its therapeutic use has been growing in other parts of the world over the last two decades. German GPs (general practitioners, primary care physicians) commonly prescribe the herb for some patients with depression, especially adolescents and children.
In most countries St. John's wort is an OTC (over-the-counter, no prescription required) medication. In others a prescription is required (for example, Ireland).
Herbalists commonly use a fluid extract rather than a tincture. Most people take the herb either in tablet or capsule form, but it is also available in teabags and tinctures (a medicinal extract in a solution of alcohol).
What is the evidence for St. John's wort's effectiveness?
According to The Mayo Clinic, USA, and some other sources, St. John's wort has been tested for the following conditions:
- Depressive disorder - for the last twenty or so years St. John's wort has been extensively studied in Europe, while US studies have occurred more recently. For the treatment of mild-to-moderate major depression, studies lasting up to 12 weeks (short-term studies) indicate that the herb is more effective than a dummy drug (placebo), as well as being as equally effective as TCAs (tricyclic antidepressants).
Although studies comparing St. John's wort against SSRIs (selective serotonin reuptake inhibitor), such as Prozac (fluoxetine) or Zoloft (sertraline) have so far been more limited, there is some evidence that the herb may possibly be just as effective, and also with fewer side effects.
The Mayo Clinic concludes that there is good scientific evidence for St. John's wort's use in the treatment of depressive disorders.
- ADHD (attention deficit hyperactivity disorder) in children - research is either unclear or unfavorable. Scientists from Bastyr University, Kenmore, Washington, found that St. John's wort was no more effective than a placebo in treating ADHD.
- Anxiety disorder - the Mayo Clinic says that there is no compelling evidence either way for the treatment of anxiety disorder. In other words, there is not enough evidence to say it is effective, and neither is there evidence to say it does not work. Further studies are needed. However, there are many doctors in Europe who say St. John's wort helps patients with anxiety disorders.
- Atopic dermatitis - a study which looked at the effectiveness of hypericum cream suggested that mild to moderate atopic dermatitis may respond positively to topical treatment.
- Burning mouth syndrome (type of pain) - the Mayo Clinic informs that it is unclear whether St. John's wort is effective. Further studies are required.
- Depression in children - currently most scientists and experts say that there is not enough compelling evidence to determine whether the herb is effective for the treatment of depression in children. Doctors in Europe may view the herb more favorably than those in the USA.
- Nerve pain - some preliminary studies have demonstrated that St. John's wort may help treat neuropathic pain. Further research is needed in this area.
- OCD (obsessive-compulsive disorder) - some reports indicate that the herb might offer some benefits for patients with OCD. However, further studies are required.
- Somatoform disorders - these are disorders that have physical symptoms which cannot be linked to an organic disease, and appear to be of psychic origin. Preliminary evidence suggests that St. John's wort may be useful in the treatment of some somatoform disorders. Results need to be confirmed with more extensive tests.
- Post-operative pain - more studies are needed in this area. So far, evidence is unclear.
- HIV (human immunodeficiency virus) - although animal studies reported some anti-viral effects of St. John's wort, one human trial did not. Because of multiple reports of considerable adverse events and interactions with HIV/AIDS medications, including PIs (protease inhibitors) and NNRTIs (non-nucleoside reverse transcriptase inhibitors), doctors advise HIV/AIDS patients to avoid taking St. John's wort.
The Mayo Clinic adds that further research is required for the treatments for peri-menopausal symptoms, PMS (premenstrual syndrome), SAD (seasonal affective disorder), social phobia and severe depressive disorder.
Dosages used in St John's wort trialsAdults - human trials have used dosages ranging from 0.17 to 2.7 milligrams of hypercin (oral), and 900 to 1,800 milligrams of St. John's wort extract (oral) daily. For the treatment of atopic dermatitis, 1.5% hyperforin (verum) has been applied to the skin.
Children - human trials with children have used from 150 to 1,800 milligrams of St. John's wort extract daily (oral), with good tolerability.
Possible side effects of St. John's wort
The majority of studies have been short-term ones (up to 12 weeks). During those periods St. John's work has generally been well tolerated at the above-mentioned doses.
If side effects do occur, they may include:
- Dry mouth
- Light sensitivity
- Sexual dysfunction
- Skin reactions
- Stomach upset
- Tiredness (fatigue)
Studies suggest that up to 3% of patients may experience side effects. Side effects are generally much less than those experienced with standard medications used for the treatment of depression.
Patients should NOT take St. John's wort if they are taking the following medications because their effectiveness may be reduced:
- Oral contraceptives
- Some anti-HIV drugs
St. John's wort should not be taken if you are taking the following medications, because it can have an additional effect on these drugs, which may cause problems:
- SSRI antidepressants (selective serotonin reuptake inhibitors)
- Triptan drugs used for migraine, such as sumatriptan
Pregnancy or breastfeeding mothers - currently, experts do not know whether or not it is safe to take St. John's wort if a mother is pregnant or breastfeeding.
The National Health Service (NHS), UK, advises patients to see their doctor first before taking St. John's wort, especially if they are already taking medications.
Lay people (in this text "non-scientists") tend to think that natural products, such as herbs are all safe, just because they are natural. This is not true. Some natural mushrooms may be good for you, while others are extremely dangerous if consumed. Examples of poisonous natural plants include aconite, balsam apple, baneberry, deadly nightshade, yew, bloodroot, foxglove, hemlock, poison ivy, white poppy. In fact, some deadly plants and herbs have been artificially manipulated and turned into life-saving medications - in other words, some plants may kill you in their natural form and save lives when artificially processed. A plant of the genus Digitalis (including foxgloves) is a source of cardioactive steroid glycosides commonly used in the treatment of some heart diseases.
Research published on the journal of Clinical and Experimental Pharmacology and Physiology in 2015 has suggested that St John's Wort can produce the same adverse reactions as fluoxetine, and serious side effects can occur when the two drugs are taken together. Dr Ian Musgrave, Senior Lecturer, Discipline of Pharmacology School of Medical Sciences at the University of Adelaide, said:
"Most people taking St John's Wort will not have any adverse reactions; however, those who do take it should tell their doctor and pharmacist."
"Based on this research, I'd also like to see bottles of St John's Wort containing improved warnings of the potential adverse reactions."