St John's Wort (also known as Hypericum perforatum) is a hardy perennial plant with glorious yellow flowers. In some parts of the world, such as Australia and North & South America, it has flourished to the extent that it's considered a noxious weed and a hazard to grazing livestock. But this humble herb has potent properties, and has been used since ancient times as a remedy for depression and nervous disorders.
Does St John's Wort help depression?
There are hundreds of clinical studies on the use of St John's Wort for depression, the majority from Germany where St John's Wort has been used successfully for years in mainstream medical practice. Overall, the research shows that St John's Wort works as well as medical anti-depressants for mild to moderate depression. It doesn't work for everybody - but then, anti-depressants don't always work, either.
Because there are so many reports & often with different results, the best way to get a good overview of the research findings is to look at meta-analysis studies. In these types of studies the researchers examine all the reports they can find that fit their criteria, and so the results are generally more reliable than those of just one study.
One of the first of these meta-analysis studies is from 1996 (Linde et al). The authors looked at 23 randomised trials that fit their criteria, covering 1757 outpatients with mainly mild or moderate depressive disorders. Fifteen of these studies compared St John's Wort with a placebo treatment, and eight compared St John's Wort with standard antidepressant treatment.
The meta-analysis found that across all studies, St John's Wort was superior to placebo, and equally as effective as antidepressant medication in improving depressive symptoms. The meta-analysis also showed 19.8% of the patients treated with St John's Wort reporting side-effects, compared with 52.8% reporting side-effects from antidepressant medication.
Although this early meta-analysis has been criticised on the grounds of the short treatment period, inadequate doses of antidepressants, and similar factors, it's generally agreed that these meta-analyses from 1996 and later have shown that St John's Wort is overall more effective than a placebo, and for people suffering from mild to moderate depression, often as effective as a standard anti-depressant (Linde et al, 1996; Stevinson & Ernst 1999; Kaspar et al, 2007).
However, until recently, the research did not support St John's Wort as a treatment for major depression.
This changed in 2008 with a pivotal meta-analysis, again by Linde et al, looking at the use of St John's Wort for major depression. This meta-analysis had strict criteria for inclusion in their results, looking at only double-blind and properly controlled studies, comparing St John's Wort either with placebo or with standard antidepressants (either tricyclics or SSRIs).
They found that across 18 trials comparing St John's Wort with placebo and 17 trials comparing St John's Wort with antidepressant medications, again St John's Wort was more effective than placebo and just as effective as the antidepressants. What's more, fewer patients in the St John's Wort group dropped out, and there were fewer reported side-effects in the St John's Wort treatment groups compared with the antidepressant treatment groups.
In spite of all these studies showing the effectiveness of St John's Wort for depression, mainstream medicine in the United States still expresses scepticism. For example, this study from 2002 looked at 340 adult outpatients diagnosed with major depression and randomly assigned to placebo group, or a group treated with St John's Wort, or a group treated with sertraline (an SSRI antidepressant) for 8 weeks. They found no differences in outcomes between the placebo group and the St John's Wort treatment group - but neither was there any significant treatment effect in the sertraline treatment group. Nevertheless, this study is still quoted as one that "fails to support the efficacy of H perforatum".
An unbiased reading of the research suggests that St John's Wort is effective in treating depression, whether mild, moderate or more serious. However, a person who is suffering from a more serious level of depression should not be self-medicating, no matter how effective the treatment. Depression can be a very serious condition indeed, and it usually does respond to proper treatment. Please get professional help if you are in this situation!
Does St John's Wort work for anxiety?
While we can say with confidence that St John's Wort can often be helpful for depression, the answer for anxiety is not quite so clear.
In fact, there are different types of anxiety, with different biochemical mechanisms, and if you have a mixed type of anxiety with depression, it's likely that St John's Wort could help relieve your anxiety as well as the depression. Many types of anxiety do respond to anti-depressants (especially SSRI anti-depressants), and if this applies to you, then St John's Wort could be worth trying.
There is one type of anxiety that does seem to respond particularly well to St John's Wort, and this is the ruminating, obsessive worrying type of anxiety.
If you are bothered by anxiety and want to try a serotonin booster, then St John's Wort would be a good one to start with. Follow the dosage guidelines and cautions given below for using St John's Wort for depression, and tweak it to suit your own situation.
How does St John's Wort work for depression?
The yellow flowers and buds of the Hypericum plant contain a whole host of compounds which may all have some therapeutic effect - and it's likely, as with all herbal remedies, that these botanical compounds work synergistically together to help relieve depression. The ones that have been identified to help depression are hypericin and hyperforin, though it's likely that the whole plant extract is more beneficial than just these identified compounds. St John's Wort, like SSRI anti-depressants such as Prozac, acts to prevent re-absoption of neurotransmitters such as serotonin and dopamine in the brain, and so effectively boosts their levels. (However, St John's Wort seems to have a slightly different mechanism for doing this.)
St John's Wort seems to have a more diffuse action than standard anti-depressants, perhaps due to the synergy of the phytochemicals it contains, and scientists are still needing to do more research to fully understand its action. However, St John's Wort is definitely a serotonin booster, and should be approached in the same way as other serotonin boosters such as 5-HTP.
Side-effects of St John's Wort
There are some side-effects and cautions for taking St John's Wort:
- As with other serotonin boosters, don't take it if you are taking anti-depressants, especially the SSRI medications. There is a risk of serotonin syndrome (though in reality you have to take a lot of medication to get to that point). Also, be careful about combining St John's Wort with other serotonin boosters such as 5-HTP.
- St John's Wort interacts with a number of other medications apart from anti-depressants. The most common problem is that it may reduce the efficacy of oral contraceptive medication. It can also interact with warfarin (used as a blood thinner), some HIV drugs (e.g. indinavir), some heart medications (e.g. digoxin), some cancer medications (e.g. irinotecan) and transplant anti-rejection medication (e.g. cyclosporine). In general, if you are already taking prescribed medication, you should ask your medical practitioner before taking St John's Wort, and if you are taking St John's Wort, you should tell your doctor if you need to have medical treatment of any kind.
- St John's Wort can make you more sensitive to sunlight - you could be more susceptible to sunburn if you expose your skin too much. This effect will probably only be mild if you take St John's Wort in normal therapeutic amounts, but it may still be significant in summer, and you should definitely avoid tanning beds and the like.
- Some people experience mild nausea or other gastric symptoms when taking St John's Wort, though this is usually mild.
- As with 5-HTP and other serotonin boosters, you should not take St John's Wort if you have BPAD (bipolar affective disorder) because it can trigger a manic episode.
- Best not to take St John's Wort if you are pregnant or breast-feeding, as we don't know enough about the risks to an unborn or young baby.
However, we can say that St John's Wort is generally safe enough on its own, and by all reports is generally well tolerated. There are no reports of major side-effects when taken in the recommended therapeutic dosage - and some of the dosages used in research trials have been many times greater than the recommended dose for effectiveness.
St John's Wort dosage
Because it's so difficult to standardise herbal extracts, the optimal dosage of St John's Wort will vary with the particular preparation and brand. However, here are some guidelines:
If you want to take St John's Wort for depression or anxiety, you probably want to plan on taking 900 mg per day, and up to 1800 mg per day. (Start with a lower dose if you prefer, to see how well you tolerate it, and build up gradually.) The recommended protocol is to take your daily dose as a divided dose, three times per day.
There are reports of some studies using higher doses than this, but if it is going to work for you, it should do so within that range.
Most of the extracts used for research studies were standardised to 0.3% hypericin and 2-5% hyperforin. However, as long as you choose a reputable brand with a quality product you can adjust your dosage as per the product recommendations.
How to take St John's Wort
Like SSRI anti-depressants, the beneficial effects of St John's Wort tend to build up over time. Taking 900 mg per day, it will likely take 4-5 days to reach a steady level in your bloodstream. Some people find that they get a positive effect almost immediately, but others find it takes time to get a noticeable result. It's reported to take around 6 weeks after you stop taking it for it to get back to undetectable levels once it reaches this steady state.
It's best to take your daily dose of St John's Wort divided into 2-3 doses during the day, to help it build up gradually and keep the level steady. However, if it works better with your schedule to take just one dose in the morning, that should not be a problem.
One more thing: St John's Wort tastes vile... so you may prefer a capsule to a liquid extract for this reason!
References & further reading
Hypericum perforatum - a good, readable summary of the current science of St John's Wort (it's efficacy and mechanism).
St John's wort for depression--an overview and meta-analysis of randomised clinical trials. Linde K, Ramirez G, Mulrow CD, Pauls A, Weidenhammer W, Melchart D. -BMJ. 1996 Aug 3;313(7052):253-8.
Hypericum for depression. An update of the clinical evidence. Stevinson C, Ernst E. -Eur Neuropsychopharmacol. 1999 Dec;9(6):501-5.
Effect of Hypericum perforatum (St John's Wort) in Major Depressive Disorder. Hypericum Depression Trial Study Group - JAMA. 2002;287(14):1807-1814. doi:10.1001/jama.287.14.1807.
St John's wort for major depression - Linde K, Berner MM, Kriston L. Cochrane Database Syst Rev. (2008) - a very thorough meta-analysis of studies researching the effectiveness of St John's Wort for major depression.
Efficacy of St. John's wort extract WS 5570 in acute treatment of mild depression: a reanalysis of data from controlled clinical trials. - Kasper S, Gastpar M, Müller WE, Volz HP, Dienel A, Kieser M, Möller HJ. Eur Arch Psychiatry Clin Neurosci. 2008 Feb;258(1):59-63. Epub 2007 Dec 14.
Medical Attributes of St. John’s Wort (Hypericum perforatum) in Herbal Medicine: Biomolecular and Clinical Aspects (Ch 11) 2nd edition - Kenneth M. Klemow, Andrew Bartlow, Justin Crawford, Neil Kocher, Jay Shah, and Michael Ritsick. - all you could want to know about St John's Wort, including summaries of research studies about efficacy, research about the biochemistry and pharmacology of St John's Wort, and history of its use.