Cannabidiol (CBD)

Properties, benefits and side effects

What is cannabidiol (CBD) and what is it used for?

Cannabidiol (CBD) is one of the two main phytocannabinoid chemicals found in the plant Cannabis sativa, alongside delta-9-tetrahydrocannabinol (THC). CBD has been used as a treatment for various ailments for thousands of years.1 The use of CBD for medicinal purposes currently differs between countries.

In 2017 the World Health Organisation officially recommended that CBD should not be ‘internationally scheduled as a controlled substance’. This led to numerous countries – including many in the European Union, the United States of America, Canada and Australia – relaxing regulations around CBD.

Within the European Union2 and the United States of America,3 CBD-containing medical cannabis products are currently used to treat  Dravet syndrome and Lennox–Gastaut syndrome, which are both rare types of epilepsy that begin in childhood and can continue into adulthood.

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CBD properties

Studies have attributed various properties to CBD, including:4



Anti-emetic (prevents sickness/nausea)





Pain-relieving CBD is often used alongside THC, both in their appropriate dosing, for medicinal purposes to improve a patient’s quality of life.

Effects on CBD for health

Research has also shown other potential benefits of CBD on health. These findings indicate that medical cannabis can have a positive effect in the relief of a variety of diseases and symptoms.

These include:

  • Sleep5
  • Anxiety6
  • Chronic pain7
  • Symptoms of rheumatoid arthritis8
  • Oncological palliative care9
  • Migraine
  • Side effects of CBD – is it safe to use?

    The most common side effect of CBD is drowsiness. Other side effects can include vomiting, diarrhoea, and changes to appetite.10

    The World Health Organisation reports CBD to be well tolerated with side effects relatively rare, nevertheless, as with any medication, you should speak with your healthcare provider for detailed instructions on how to proceed with the therapy. If you experience any adverse effects, then do contact your doctor or prescriber.

    • Pregnancy
    CBD should not be taken in pregnancy as there is evidence to show it can cross the placenta barrier.11 Likewise, it can pass through breastmilk to a breastfed baby, so breastfeeding women should not take CBD.
    • Children
    The use of CBD therapy in younger children is primarily tailored around treatment for epilepsy and dosage should be carefully managed by a paediatrician.

    Is CBD addictive?

    No. The World Health Organisation’s Expert Committee on Drug Dependence declared that CBD presents no potential for abuse or dependence.12

    Does CBD affect driving?

    You can drive after taking CBD, but clearly if you feel drowsy it would not be responsible to get behind the wheel. A 2020 study that saw participants carry out on-road driving tests after consuming CBD found it had little effect on people’s driving or cognitive abilities. However, as the compound can affect individuals differently, it’s probably best not to drive the first time you take it.

    Are there long-term effects of CBD?

    In most cases there are no long-term effects of CBD use, although there is little research into this area. If CBD is taken regularly for an extended period of time, then a tolerance could develop which would mean a higher dosage would be needed to create the same result.

    CBD and THC for medical cannabis


    Medical cannabis products contain either primarily CBD or THC or a combination of both compounds.

    The properties vary between them. THC is a psychoactive which means it causes changes in mood, awareness, thoughts, feelings, or behavior.  It can change the perception to pain and reduce  the symptoms of anxiety and nausea.13 On the other hand, CBD is not a psychoactive substance and is known to have anti-inflammatory and antioxidant properties. 14


    1 Russo E. History of cannabis and its preparations in saga, science, and sobriquet. ChemInform. 2007;38(47):1614-1648. doi:10.1002/chin.200747224

    2 European Medicines Agency. Epidyolex. Published 2022. Accessed August 25, 2022.

    3 US Food and Drug Administration. FDA approves first drug comprised of an active ingredient derived from marijuana to treat rare, severe forms of epilepsy. Published 2018. Accessed August 25, 2022.

    4 Atakan Z. Cannabis, a complex plant: different compounds and different effects on individuals. Ther Adv Psychopharmacol. 2012;2(6):241-254. doi:10.1177/2045125312457586.

    5 Babson K, Sottile J, Morabito D. Cannabis, cannabinoids, and sleep: a review of the literature. Curr Psychiatry Rep. 2017;19(4):23. doi:10.1007/s11920-017-0775-9

    6 Schier A, Ribeiro N, e Silva A et al. Cannabidiol, a Cannabis sativa constituent, as an anxiolytic drug. Braz J Psychiatry. 2012;34(Suppl. 1):S104-S117. doi:10.1016/s1516-4446(12)70057-0

    7 Urits I, Gress K, Charipova K et al. Use of cannabidiol (CBD) for the treatment of chronic pain. Best Pract Res Clin Anaesthesiol. 2020;34(3):463-477. doi:10.1016/j.bpa.2020.06.00

    8 Malfait A, Gallily R, Sumariwalla P et al. The nonpsychoactive cannabis constituent cannabidiol is an oral anti-arthritic therapeutic in murine collagen-induced arthritis. Proc Natl Acad Sci USA. 2000;97(17):9561-9566. doi:10.1073/pnas.160105897

    9 Wang F, Multhoff G. Repurposing Cannabidiol as a Potential Drug Candidate for Anti-Tumor Therapies. Biomolecules. 2021 Apr 15;11(4):582. doi: 10.3390/biom11040582. PMID: 33921049; PMCID: PMC8071421

    10 Huestis MA, Solimini R, Pichini S, Pacifici R, Carlier J, Busardò FP. Cannabidiol Adverse Effects and Toxicity. Curr Neuropharmacol. 2019;17(10):974-989. doi:10.2174/1570159X17666190603171901

    11 Dong C, Chen J, Harrington A, Vinod KY, Hegde ML, Hegde VL. Cannabinoid exposure during pregnancy and its impact on immune function. Cell Mol Life Sci. 2019;76(4):729-743. doi:10.1007/s00018-018-2955-0

    12 World Health Organisation. News Briefing – 40th WHO Expert Committee on Drug Dependence (ECDD). Published 2018. Accessed August 25, 2022.

    13 Lucas P, Walsh Z. Medical cannabis access, use, and substitution for prescription opioids and other substances: A survey of authorized medical cannabis patients. Int J Drug Policy. 2017;42:30-35. doi:10.1016/j.drugpo.2017.01.011

    14 Atalay S, Jarocka-Karpowicz I, Skrzydlewska E. Antioxidative and Anti-Inflammatory Properties of Cannabidiol. Antioxidants (Basel). 2019;9(1):21. Published 2019 Dec 25. doi:10.3390/antiox9010021