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The Royal College of Psychiatrists Improving the lives of people with mental illness

Complementary and Alternative Medicines 1

Under Review April 2018


Herbal remedies and supplements

This leaflet is for anyone who would like to try complementary medicines for a mental health problem. It covers:

What are complementary and alternative medicines (CAMs)?

They are ways of treating illness that have developed outside the mainstream of modern medicine. Many are traditional remedies that have developed in different cultures over the centuries. They include:

  • herbal medicines
  • foods
  • nutritional supplements, such as vitamins and minerals

 All these treatments can be used on their own, or with conventional medicine.


CAMs and mental health problems

Many CAMs have been used for mental health problems, but there is little good evidence to support their use. Some of these treatments may work, but most have not been thoroughly tested. The studies have often been too small to give a clear answer. We know most about the treatments for depression, anxiety and insomnia.


Despite the lack of evidence, people all over the world take CAMs, and many report that they find them helpful. Ultimately, whether taking CAMs is a good idea depends on individual circumstances. We recommend that you talk to your GP or mental health team first.

If you are considering taking CAMs, you should seek specialist advice if:

  • you are  pregnant or breastfeeding
  • you want to give CAMs to children
  • you are competing in sports to make sure that the CAM you are considering taking is not in breach of doping regulations.

How to use CAMs safely?


  • choose a qualified practitioner who is a member of a recognised society
  • ask about their qualification and experience
  • ask about side-effects
  • if in doubt, ask your doctor, nurse or pharmacist
  • tell the professionals involved in your care, including your CAM practitioner, about all your treatments and medications
  • tell them if you are pregnant, plan to become pregnant or breast-feed
  • tell them about your physical health and allergies
  • discuss your concerns about treatment
  • seek medical advice if you experience unusual symptoms
  • make special time for your treatment sessions
  • find a reliable source for your information about therapies.


  • stop conventional medicines without telling your doctor
  • believe claims for 'wonder cures'
  • take high doses of supplements unless confirmed with an experienced health professional
  • combine many different remedies
  • take complementary medicines without knowing what they are for
  • take somebody else’s complementary medicines
  • give remedies to children without seeking specialist advice
  • take remedies from an unreliable source - this includes the internet
  • eat or drink raw plant material, such as flowers, fruits, leaves, seeds or the root unless you are sure it is absolutely safe (many plants are poisonous and need to be processed before they can be used safely)
  • prepare your own teas and extracts unless you are sure it is safe
  • smoke raw plant material
  • pay large sums of money up front
  • practice acupuncture or any other physical treatment on yourself unless you have been trained
  • blame yourself if a treatment does not work.

Herbal remedies and supplements

Herbal remedies come from plants. If possible, choose a remedy which has been standardised, i.e. the contents are approximately the same in each bottle or tablet you buy. Plant remedies are not always safer than ordinary medicines. All of them can have side-effects and interact with other medicines.


Supplements include vitamins, minerals and animal and plant products, such as cod liver oil. They can also have side-effects and interact with other medicines. Some people take supplements, like vitamin C in high doses, but this can damage the liver or kidneys. Many supplements have a recommended daily intake (RDI), or allowance (RDA). Do not go beyond this dose without talking to an experienced health professional.


Brain function and dementia

These are called 'cognitive enhancers' and can improve concentration. They include:

  • Ginkgo (ginkgo biloba)
  • Ginseng (panax ginseng)
  • Hydergine (Ergot) (claviceps purpurea)
  • Sage (Salvia officinalis, salvia lavandulaefolia)
  • Vitamin E (alpha-tocopheril)


Ginkgo is a tree originating in China. Extracts of its seeds and leaves are used to improve thinking in healthy people, as well as people with dementia.

How does it work?

We don't know. It may:

  • act as an antioxidant to prevent cell damage
  • increase the blood flow in the brain or increase chemical transmitters in the brain.

How good is it? Research shows that Ginkgo may help in dementia. The same is true of its use in healthy adults, but ultimately, we do not know.

Side-effects: It may rarely cause bleeding into the brain and into the eye or prolong bleeding time during surgery. About twenty such cases have been reported, and patients undergoing surgery may consider avoiding gingko. Gingko should not be taken together with blood thinning medications, such as aspirin and ibuprofen. There is an increased risk of fits and lower fertility in both men and women. 

Drug interactions with:

  • blood thinning drugs such as aspirin, ibuprofen, warfarin (increases bleeding time)
  • trazodone (one case of coma has been reported)
  • antidepressants (increase the risk of going high - mania)
  • anticonvulsants (reduces their effectiveness).


Ginseng grows in many parts of the world. Panax ginseng or Korean ginseng are most commonly used.Ginseng

How does it work?

We don't know. It may:

  • thin the blood
  • prevent cell damage through antioxidant activity.

How good is it? It might improve cognitive performance, but there is no evidence that it delays ageing. 

Side-effects: agitation and mania; sleep problems; blood pressure changes; changes in bleeding time so people with bleeding disorders such as stroke and blood clots (thrombosis) should avoid it. It may possibly stimulate breast cancers.

Drug interactions with:

  • drugs used in diabetes (lower blood sugar)
  • blood thinning agents such as aspirin, ibuprofen and warfarin (changes in bleeding time)
  • MAOI antidepressants (eg. Phenelzine), may lead to agitation and sleep problems.


This comes from a fungus which lives on rye. For hundreds of years it has caused epidemics of poisoning (ergotism). This is caused by eating bread made from infected rye flour.

How does it work?

  • It may affect the activity of brain transmitters.

How good is it? It may improve memory in dementia.

Side-effects: It can cause fits, confusion, hallucinations and psychosis. Severe poisoning can cause gangrene.

Drug interactions with:

  • antidepressants and some pain killers
  • drugs for dementia
  • drugs for migraine.


Sage produces oils which are used in aromatherapy. It is used to improve concentration and memory and has Sagebeen suggested as a treatment of depression and anxiety.

How does it work?

It may:

  • increase some brain transmitters
  • have antioxidant, anti-inflammatory and oestrogen effects

How good is it? There is some evidence for improved memory in volunteers. One study found that it improved mood, alertness, calmness and contentedness. It may help concentration in people with dementia.

Side-effects: although safe when used in amounts commonly found in foods, some types when taken orally can cause convulsions. Sage may also lower blood sugar. It should not be used in pregnancy or when breastfeeding.

Drug interactions with:

  • drugs for diabetes 
  • drugs for epilepsy 
  • sedatives.

Vitamin E (alpha-tocopherol)

Vitamin E is found in plant oils, nuts, vegetables and, to a lesser degree, in meat and dairy products.

How does it  work?

  • Antioxidant properties may prevent cell damage.

How good is it? It may improve behaviour in dementia, but there is no good evidence that it improves memory or slows the progress of the disease.

Side-effects: A recent study found that a daily intake of more than 400IU (270 mg of alpha-tocopherol) resulted in an increase of death from all causes, and an increased risk of bleeding and stroke.

Drug interactions with:

  • drugs to thin the blood
  • anaesthetics and cocaine
  • drugs to lower cholesterol and some cancer treatments.

Anxiety and Sleep Problems

Most of these treatments seem to work on gamma-amino-butyric acid (GABA), a chemical in the brain linked to anxiety. We do not know if these drugs cause addiction. They are less powerful than conventional sedatives or sleeping tablets. 



  • Kava (piper methysticum) has been withdrawn in the UK due to concerns that it might cause liver damage. It should not be used.
  • Combinations of extracts may be less safe. There have been concerns about liver damage from combinations of valerian and other herbs.

Remedies include

  • Valerian (valeriana officinalis)
  • Passion flower (passiflora incarnata)
  • German chamomile (matricaria recutita)
  • Hops (humulus lupulus)
  • Oats (avena sativa)
  • Starflower / borage (borago officinalis)
  • Lemon balm (melissa officinalis)
  • Lavender (lavendula angustifolia)
  • Bach flower remedies
  • Melatonin (N-acetyl-S-metoxy tryptamine)
  • Aminoacids
  • Roseroot
  • Vitamins, trace elements and supplements


Valeriana officinalis is thought to be safe and is available as a standard extract in the UK. Some other species Valerianmay cause liver problems

How does it work?

  • It probably acts on GABA.
  • It may also counteract the effects of caffeine.

How good is it? This remains unclear at the moment, but some studies have shown that people report sleeping better having taken Valerian.

Side-effects: drowsiness or excitability. It may slow down reactions, so you should not drive or operate dangerous machinery after taking it. Valerian is safe more most people when used sort-term. As with most complementary medicines, we do not know whether long-term use may be harmful. You should not take it in pregnancy.

Drug interactions with:

  • sedatives
  • alcohol
  • the pill
  • HIV medicines
  • cancer treatments
  • epilepsy and anti-fungal treatments
  • blood thinning medicines.

Passion flower

passionPassion flower is used to treat anxiety. It has also been suggested as a treatment in alcohol craving and opiate withdrawal.

How does it work?

  • It probably acts on GABA.

How good is it? Very few studies have been conducted, One trial found it to be as good as conventional tranquillisers.

Side-effects: isolated reports of severe toxicity even at normal doses. It can cause dizziness, confusion, heart problems, and inflammation of blood vessels. Some species may contain cyanides, so toxicity may depend on the preparation.

Drug interactions with:

  • warfarin, a blood thinner.

German chamomile

chamomileChamomile is a mild sedative.  It is also used to treat stomach upsets and mucosal irritations. Traditionally the flowers are prepared as a tea.

How does it work?

  • It acts on GABA.

How good is it? We know very little, but one recent study has shown that it may make people less anxious, as long as the anxiety is not too bad.

Side-effects: it may increase bleeding time and may stimulate breast cancer cell growth in oestrogen sensitive cancers.

Drug interactions with:

  • blood thinning drugs
  • oral contraception (the pill).


Hops plantDried hops have been used to treat anxiety and sleep problems.

How does it work?

  • We don't know.

How good is it? One study showed that a valerian-hops combination helped sleep.

Side effects: none reported.

Drug interactions with: increases sedation when used with:

  • sedatives
  • sleeping tablets
  • other herbs
  • alcohol.


People use this to lower cholesterol and for stomach upsets, such as irritable bowel syndrome. It has also been Oatsused to treat anxiety and tiredness. It has even been suggested for use in alcohol and nicotine addiction.

How does it work? We don’t know.

How good is it? We don’t know.

Side-effects: none known.

Drug interactions with: none known.


Starflower (borage)

Starflower plantStarflower oil is used for rheumatoid arthritis, premenstrual syndrome (PMS) and sedation.

How does it work?

  •  We do not know.

How good is it? We do not know.

Side-effects: some extracts can cause liver problems or possibly cancer. It should not be used in pregnancy and it may increase epileptic fits.

Drug interactions with:

  • blood thinning drugs such as: aspirin, ibuprofen, warfarin.

Lemon balm

Lemon balm is a herb of the mint family. It is used for anxiety, sleep problems, heavy periods and period pain. It is also used to treat agitation in dementia. Lemon balm is used as tea or extract. The oil is also used in Lemon Balmaromatherapy.

How does it work?

  • It may work on brain transmitters. 

How good is it?  Some evidence of calming in dementia. No research on its use in anxiety and insomnia. In combination with valerian and hops, it can improve sleep.

Side-effects: very few

Drug interactions with: increases sedation when used with:

  • sedatives
  • herbs
  • alcohol.


lavenderLavender is also a member of the mint family. Drops of lavender oil or seeds put onto pillows have been used to help sleep. It is used in aromatherapy, and as an extract or tea.

How does it work?

  • We don't know.

How good is it? May act as a mild sedative when used in aromatherapy.

Side-effects: skin irritation.

Drug interactions with: increased sedation when used with:

  • sedatives
  • herbs
  • alcohol.

Bach flower remedies

This is an extract from a combination of flowers which is used to treat anxiety, panic and trauma.

How does it work? We don’t know.

How good is it? No good evidence.

Side-effects: We don’t know.

Drug interactions with: We don’t know.


Melatonin is a hormone made by the pineal gland in the base of the brain. It controls our body clock. If you are over 55, your doctor can prescribe melatonin for you. The prescribed brand is called Circadin.

How does it work?

  • By regulating the body clock.

How good is it? It may improve sleep quality in older adults.

Side-effects: sleepiness and low mood.

Drug interactions with: blood thinning drugs.

Increases sedation when used with: sedatives and herbs.


A mixture of two aminoacids - L-Arginine and L-Lysine - has been used to try to reduce stress and anxiety.

How does it work? By modifying hormones which are released under stress.

How good is it?  Only a few studies exist so we don't know.


  • L-Lysine: one case of severe kidney problems has been reported.
  • L-Arginine: drugs which lower blood pressure and nitrates. A few deaths have occurred in people who had a recent heart attack. If in doubt, avoid or seek an opinion from a heart specialist first.

Drug interactions with:

  • L-Lysine: calcium supplements.
  • L-Arginine: drugs which lower blood pressure and nitrates. Avoid such combination because they may make your blood pressure fall too much.  Even combination with medicines, such as Viagra, may make your blood pressure go too low.


RoserootRoseroot is also known as 'arctic root' or 'rhodolia'. It is also a so called 'adaptogen' which should help the body cope better with stress, anxiety and tiredness. Roseroot has also been used as an energy booster, for instance to enhance athletic performance.

How does it work?

  • We don't know. Some components of roseroot may modify hormones which are released under stress, others may be mildly stimulating.
  • It also has antioxidant activity.

How good is it?  We don't know at present. More studies are needed to confirm the effects.

Side-effects: No serious effects reported. It may cause dizziness or dry mouth.

Drug interactions with: None reported.

Vitamins, trace elements and supplementsIt has been suggested that certain vitamins, trace elements and supplements may help anxiety. However, there are very few studies to rely on at present. One problem is that studies tend to test combinations rather than individual substances, so that it's difficult to tell which ingredient does what.

The Food Standards Agency has produced a website which explains all about vitamins, trace elements and supplements.

Depression and Bipolar Disorder

Remedies include:

  • St John’s wort (hypericum perforatum)
  • S-adenosyl-methionine
  • Folic acid (Folate)
  • Selenium
  • Vitamin D
  • Omega-3 fatty acids

In bipolar disorder (manic depression), adding omega-3 fatty acids may reduce the chance of becoming ill again. Some people buy natural lithium, but we do not recommend this because the doses offered in the tablets are much lower than in prescription preparations. Also, lithium at any dose should be closely monitored.


Most treatments for depression are supplements, which are building blocks in the production of serotonin. This is a chemical in the brain that seems to be involved in depression. L-tryptophan and 5 hydroxytryptophan (5-HT), are such building blocks, but they have not as yet been cleared as safe.


St John's wort

stjohnsSt John’s wort gets its name from St John’s day on the 24th June. This is when the plant starts to flower. For a long time it was thought that the red dye, hypericin, which is produced when the plant is crushed, was responsible for its action. Research now suggests that another ingredient, hyperforin, may produce the antidepressant effect. St John’s wort has also been suggested as a treatment of anxiety, addiction and premenstrual stress.

How does it work?

  • Increases serotonin in the brain.

How good is it? It has been shown to be effective in many trials.

Side-effects: People taking St John’s wort may burn more easily in the sun; if in doubt use sun screen. It may cause mania in people with bipolar disorder.

Drug interactions with:

  • antidepressants
  • strong painkillers
  • oral contraceptives (the pill), reduces its effectiveness
  • some cancer drugs.

Can also reduce the effect of:

  • some epilepsy drugs, such as carbamazepine
  • digoxin
  • warfarin
  • HIV drugs
  • some cancer drugs.

There is also a risk of organ rejection in people taking St John's wort who undergo transplant surgery.


S-adenosyl-methionine (SAME)

S-adenosyl-methionine (SAME) is another building block of serotonin. It is not often used in the UK, but is popular in Europe and the US. It is also popular with HIV sufferers because it has few side-effects. It is often given as an injection. However, oral preparations are available, but some do not work. SAME can be expensive.

How does it work?

  • It helps to produce serotonin and other neurotransmitters.

How good is it? Some trials show that SAME has a good antidepressant effect.

Side-effects: may cause mania in people with bipolar disorder.

Drug interactions with:

  • antidepressants
  • strong painkillers.

Folic acid (Folate)

Folic acid is used by women who want to become pregnant or are pregnant to prevent spina bifida, a malformation of the baby’s spine. In some countries, folic acid is added to the flour.

How does it work?

  •  It is another building block of serotonin and other neurotransmitters.

How good is it? It may increase the effect of some antidepressants.

Side-effects: It may make it more difficult to diagnose pernicious anaemia which can occur in people who do not have enough Vitamin B12. Large doses can cause agitation, sleep problems, confusion and fits.

Drug interactions with:

  • some anti-cancer drugs
  • some antibiotics.


Selenium is an important trace element. It is found in vegetables, meat, fish and Brazil nuts. Brazil nuts can vary in selenium content, but sometimes the concentration is so high that the US National Institutes of Health advise that Brazil nuts should be only eaten occasionally. The Food Standards Agency recommends a safe upper level of 0.45 mg per day. Some formulations exceed this dose.

How does it work?

  • Selenium is an antioxidant and may prevent cell damage. It also helps produce thyroid hormone.

How good is it? We don’t know.

Side effects: can lead to nausea, vomiting, nail changes, irritability, weight loss, depression, confusion, liver and skin changes.

Drug interactions with:

  • drugs to lower cholesterol
  • vitamin preparations.

Vitamin D

How does it work?

  • Vitamin D helps to grow and to protect nerve cells in the brain. Vitamin D is also an antioxidant and helps to produce neurotransmitters, such as dopamine and noradrenaline.

How good is it? We don't know. Many depressed people may have low vitamin D levels, but studies have not been able to show that taking Vitamin D helps depression.

Side-effects: Taking high dose Vitamin D may lead to kidney problems and increase calcium levels in the blood.

Drug interactions with: drugs that lower blood pressure and regulate heart beat.

NOTE! Going out into the sunlight is a good way to stock up on Vitamin D because the light of the sun helps our skin to produce Vitamin D itself. And the physical activity can help to lift low mood as well.

Omega-3 fatty acids

Omega-3 acids are mainly derived from fish – they are used to prevent heart and joint disease. They are also used in depression. Omega-3 fatty acids have two main components: docosahexaonic acid (DHA) and eicosapentaonic acid (EPA). The pills are often large, and some people find them hard to swallow. Avoid preparations which have added vitamin A. This could cause vitamin A poisoning.

How does it work? 

  • Omega-3 fatty acids help to build up and protect brain cells.

How good is it? They may be worth taking with antidepressants. They may help prevent relapse in bipolar disorder. There is not enough evidence to recommend them as an alternative to antidepressants or mood stabilisers.

Side-effects: unknown

Drug interactions with: blood thinning drugs.



Choices are limited. Rauwolfia, a plant originating from India, has been used, but is not as good as antipsychotic medicines. Reserpine, a drug developed from Rauwolfia, can cause depression and is no longer used in the UK.


Omega-3s may be tried with antipsychotic treatment, but there is no good evidence that they help. Many antipsychotics can cause weight gain and lead to a higher risk of heart and blood pressure problems. Omega-3s may reduce these changes, but success is not guaranteed.


Movement Disorders

Many older antipsychotics could cause abnormal movements, known as tardive dyskinesia. If this occurs, the dose of the antipsychotic can be lowered, or an alternative antipsychotic given.

Two complementary remedies may help -  vitamin E, melatonin and ginkgo biloba.

Vitamin E, may prevent the movements getting worse. However, the potential benefits need to be offset against long-term use, particularly if high doses of vitamin E are considered.

Melatonin has also been tried, but the research is inconclusive.

One study found that Gingko biloba can reduce tardive dyskinesia and that the effect may last for some time, even after Ginkgo biloba has been stopped. As mentioned above, there may be health risks because of a potentially increased bleeding risk.


The choice is limited. Valerian has been suggested to improve sleep in people withdrawing from drugs like Valium. But no good research has been done. Passion flower was effective when combined with clonidine in one small study, and St John’s wort may reduce alcohol craving.

Other Remedies include:

  • Kudzu
  • Iboga


Kudzu, or 'Japanese arroweed' flowers have a pleasant fragrance. They have been used for many medical purposes, including menopausal problems. It has also been used for alcohol problems.

How does it work?

  •  It may reduce anxiety caused by alcohol withdrawal. 

How good is it? One study showed reduction in alcohol use in heavy drinkers. Another study failed to show any effect on craving.

Side-effects: none reported.

Drug interactions with:

  • blood thinning drugs
  • oral contraceptives (the pill)
  • drugs for diabetes


Iboga is a West African shrub producing ibogaine. This causes hallucinations and has been used widely for religious rites. It became famous as a treatment for opiate addiction in the 60s. However, it can have serious life-threatening side-effects. Until these safety concerns are clarified it cannot be recommended.

How does it work?

  • It probably affects several chemical transmitters in the brain.

How good is it? It may help in withdrawal and in staying away from drugs.

Side-effects: Several deaths after ibogaine use have been reported. The risk of death may be as high as 1 in 300 treatments. It is not known how many deaths have occurred, and may have gone unreported because of the 'underground nature' of ibogaine treatment.

Drug interactions with:

  • drugs which affect the same neurotransmitters.

Finding a Practitioner

Finding a well-trained practitioner can be difficult. You can also always ask your general practitioner (GP) or mental health professional.


It may be useful to consult with your local drug information service, and to find a health professional with special expertise in this area, or use services recommended by your GP or hospital. There are professional herbalists who belong to the National Institute of Medical Herbalists. They are trained and often work in a private setting. Most are not medically qualified.


Useful websites

Food and Behaviour Research: this website has information about a wide variety of conditions where behaviour, learning and mood are linked with food and nutrition. You can browse this information by condition.

MedlinePlus: This is a website run by the US National Institute of Health. The homepage has a search option allowing you to type in different keywords so you can retrieve the information you want. Typing the keyword “alternative medicine” or “drug information” will direct you to the relevant sites.

Mayo Clinic: Nutrition and healthy eating. An American website that offers a wealth of information on all aspects of eating and weight control.

NHS choices: Complementary and alternative medicines. This website is very helpful to get information on all aspects of complementary alternative medicines, ranging from individual treatment to regulation of medicine, and how to find a practitioner.

National Centre for complementary alternative medicines / National Institute of Health: This US website provides comprehensive information on complementary medicines. It is easy to surf. Of particular interest is the clinical trial register which gives an overview of American research. This needs to be complemented with information from other clinical trial databases, for instance the Cochrane collaboration . Click on “news and events” for important safety updates.


Natural Medicines Comprehensive Database: A subscription-only website with extremely detailed and comprehensive information on all types of natural medicines. It is cross-referenced with the scientific literature, and contains features such as a natural product effectiveness and drug interaction checker. It also allows condition-specific searches and offers tutorials on specific topics. Patient hand-outs can be downloaded.


Quackwatch: A non-profit corporation whose purpose is to combat health-related frauds, myths, fads, fallacies, and misconduct. This website can be helpful when unusual treatments are suggested, particularly if a lot of money is to be paid in advance. Some people may find the website too provocative and sceptical - click onto the “cheers and jeers” section to get a flavour of the site.


Click here for the full list of References.

This leaflet was produced by the Royal College of Psychiatrists' Public Education Editorial Board.

This leaflet reflects the best available evidence at the time of writing.

Under Review April 2018
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