Can herbs cure depression?

Published: 21-10-2020

Last modified: 17-09-2021

Herbal medicines are often considered safer for health and as effective or even better than “chemical” drugs. In the treatment of depression, St. John’s wort is most often indicated, but you can also read about other herbal preparations helpful in the treatment of this disease. What do scientific studies say about their effectiveness?

St. John’s wort in the treatment of depression

St. John’s wort (Hypericum perforatum) has different uses depending on the form. Water extracts are mainly used in ailments of the digestive system, while alcoholic extracts are used in the treatment of depression. This plant is the best-studied natural remedy for depression.

The effectiveness of St. John’s wort

Studies on the effectiveness of St. John’s wort in the treatment of depression have been going on for over 30 years and indicate that the plant may be effective in the treatment of mild to moderate depression. The first summary of studies on this subject was made by Linde et al. In 1996. Their meta-analysis showed that St. John’s wort is more effective than placebo, and authors of other meta-analyzes have reached similar conclusions. There are also studies showing that the effectiveness of St. John’s wort is similar to that of some antidepressants (tricyclic drugs and selective serotonin uptake inhibitors), and one study has shown that this herb is effective in preventing depression recurrence.

However, research into the effectiveness of St. John’s wort is not without its drawbacks. Methodological shortcomings include the short period of St. John’s wort use, too low doses of antidepressants in studies comparing their effectiveness to St. John’s wort, heterogeneous diagnostic groups of patients and the use of different doses of St. John’s wort. All this makes it difficult to compare test results and draw conclusions. In general, newer studies that are methodologically better tend to show less efficacy of this herb than older studies.

The mechanism of action of St. John’s wort

How St. John’s wort works has not yet been discovered, although researchers have some hypotheses.

The antidepressant effect may be demonstrated by hyperforin, which is an inhibitor of serotonin, noradrenaline, dopamine, GABA and glutamine reuptake.

Another hypothesis is that hypericin affects the immune system. According to this hypothesis, this substance inhibits the production of interleukins (IL-6 and IL-1b), which reduces the secretion of corticoliberin by the hypothalamus, which in turn leads to a lower production of corticotropin by the pituitary and lower secretion of cortisol by the adrenal glands.

St John’s wort has also been shown to affect the activity of the MAO-A enzyme and the serotonin receptors 5HT1A and 5HT2A, but it seems that the effect is too weak to have an antidepressant effect.

Safety of the use of St. John’s wort

The belief that herbal medicines are 100% safe and can be always used without risk of side effects is wrong.

St John’s wort actually has fewer side effects than antidepressants. The most common side effects include gastrointestinal disturbances, allergic reactions, fatigue, dry mouth, dizziness, and headache. In some cases, and after overdose, photosensitivity may occur. However, the frequency of these symptoms is low and significantly fewer patients abandon St. John’s wort therapy than with standard antidepressants.

When deciding to take St. John’s wort, however, be aware of its interactions with other medications. Without consulting a doctor, St. John’s wort should not be used together with standard antidepressants or other psychotropic drugs (interacts with clomipramine, citalopram, alprazolam, clozapine, sertindole, aripiprazole, zopicolone, diazepam). The use of St. John’s wort together with some psychotropic drugs can lead to a dangerous serotonin syndrome.

The ingredients of St. John’s wort also activate the enzyme CYP3A, which is involved in the metabolism of, among others, contraceptives, immunosuppressants (cyclosporins), drugs used in diseases of the blood system (digoxin, warfarin) and asthma (theophylline). Taking St. John’s wort with these medicines may lower the blood levels of these medicines and make them less effective. St John’s wort also interacts with some medicines used to treat HIV infection and with triptan (a medicine for migraine).

Saffron in the treatment of depression

Saffron is a substance obtained from an autumn crocus (Crocus sativus). In recent years, several clinical trials have been published showing its effectiveness in the treatment of mild to moderate depression. The results showed that the effectiveness of saffron was superior to placebo and similar to some antidepressants (imipramine and fluoxetine). All the studies conducted were of good quality, but at the same time they all come from one research center in Iran and have not yet been replicated in other centers.

How does saffron work? Possible mechanisms are inhibition of monoamine or serotonin reuptake, action on gabaergic and NMDA receptors, or effects on nervous tissue, by e.g. activation of BDNF.

Like St. John’s wort, saffron rarely causes side effects. In rare cases, however, it may cause symptoms such as nausea, indigestion, changes in appetite, headache, increased heart rate, restlessness or allergic reactions. It can also enhance the effects of drugs for high blood pressure, blood clotting, and drugs for asthma and diabetes.

Other herbs in the treatment of depression

Other herbal remedies that may be effective in treating depression include:

• lavender,
• borage (starflower),
• Rhodiola rosea (Arctic root, golden root),
• camomile,
• ginseng.

In the case of these herbs, however, it is too early to draw conclusions. So far, only single studies have been conducted that indicate their beneficial effect in depression.

References:

1. Gałuszko M., Cubała W. J. (2005). Rola dziurawca w leczeniu depresji. Psychiatria, 2(2), 93-96. (pdf at viamedica.pl)
2. Koszewska I. (2003). Dziurawiec zwyczajny w leczeniu depresji. Farmakoterapia w Psychiatrii i Neurologii, 2003, 1, 45-54. (pdf at ipin.edu.pl)
3. Szafrański T. (2014). Leki ziołowe w leczeniu depresji – aktualny stan wiedzy. Psychiatria Polska, 48(1), 59-73. (pdf at strona.ppol.nazwa.pl)

Source of picture: Leslie Seaton from Seattle, WA, USA (St. John’s Wort (Hypericum perforatum)) [CC BY 2.0], Wikimedia Commons

Author: Maja Kochanowska