The government is reviewing the legal status of cannabis products as parents of children with severe and hard-to-treat epilepsy say it’s the only thing that helps control their kids’ daily seizures.

Recently, 12-year-old Billy Caldwell made headlines when UK Customs officers confiscated seven bottles of cannabis oil from his mother, Charlotte Caldwell, who had flown to Canada to bring the product back.

Billy and his parents were eventually allowed to take the oil back to their home in Northern Ireland, but only after being granted a special temporary Home Office licence. Other parents of children with severe epilepsy – who may experience hundreds of seizures a day – say that they’re being forced to break the law and obtain products of dubious quality in their attempts to obtain medicinal cannabis.

What is ‘medicinal cannabis’?

The cannabis plant contains many different compounds called cannabinoids. The two most significant ones are tetrahydrocannabinol (THC) and cannabidiol (CBD). While THC is the compound that gets recreational cannabis users high, CBD is of great interest to researchers for its medical properties. On its own, CBD has shown promise in the treatment of many health problems, including multiple sclerosis, epilepsy, anxiety, Alzheimer’s, schizophrenia, pain and Tourette’s.

Only one CBD-based drug is licensed for use in the UK. This is Sativex, used for the treatment of multiple sclerosis. It contains CBD and THC and has undergone stringent safety testing and clinical trials. Epidiolex, a highly-purified form of CBD used to treat epilepsy, has been approved in the US but is still awaiting approval for use in the EU.

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With cannabis-based drugs for epilepsy and other disorders such as anxiety not yet available in the UK, people are seeking out unregulated cannabis oils and other products from online suppliers or abroad.

What is cannabis oil?

Cannabis oil is a general term for any liquid extract that’s made from cannabis or hemp plants. Dr David Potter, a cannabis expert involved in both the production of medical-grade CBD and the analysis of illicit cannabis, says these products can vary hugely in terms of how they’re made and what they contain. “Some of the oils we’ve analysed are quite close to what they say they contain, others are way off,” he says. The oils are often marketed as food additives to avoid having to adhere to the strict quality standards required of medicines.

How does CBD work?

CBD is just 1 of over 100 compounds known as cannabinoids that are found in the cannabis plant. These substances act on our ‘endocannabinoid system’, a complex part of the nervous system that helps regulate a variety of processes – including our sleep cycle, appetite, pain sensation, mood and memory.

Cannabinoids like CBD and THC bind to receptors in this system throughout the body and brain, sometimes activating them and sometimes suppressing or blocking them.

The exact reason CBD appears to be so useful in treating various disorders is unclear. It does not have the intoxicating effects of THC, and intriguingly seems to have almost the exact opposite effect to high doses of THC. Research shows that CBD has appetite-suppressing properties, unlike the famous cannabis-induced ‘munchies’, and it has anti-anxiety and anti-psychotic properties as opposed to the paranoia and psychosis induced by high-doses of THC. It is these properties that have led to people purchasing CBD oil to try to alleviate problems such as insomnia and anxiety.

Is cannabis oil legal in the UK?

According to the Home Office, any material that contains THC is a Schedule 1 drug, meaning it’s classed as having no therapeutic value and is illegal. Despite breeders developing plants with high CBD levels and low THC levels, it’s impossible to breed a cannabis plant that contains no THC at all. Therefore, many cannabis oils are likely to contain small amounts of THC as well as CBD. According to the Home Office, any material that contains more than 0.05 per cent THC is a Schedule 1 drug, meaning it’s classed as having no therapeutic value and is illegal. Currently in the UK there is one brand of CBD oil that contains less than 0.05 per cent THC and is now available in high street shops such as Holland & Barrett.

What about the rest of the world?

Similar debates about medicinal cannabis are playing out all around the world. In Canada, high-strength CBD-based products are legal to buy in shops; Canada was where Billy Caldwell’s mother obtained the high-strength cannabis oil confiscated in the UK – she’s also the director of a cannabis oil company out there. However, in other countries, all cannabis products remain completely illegal.

Will cannabis be made legal in the UK soon?

In June, England’s chief medical officer Dame Sally Davies published a report concluding that there was now evidence of ‘therapeutic benefit’ from some CBD-based cannabis products. After further pressure from campaign groups, UK home secretary Sajid Javid has allowed specialist doctors in the UK to legally prescribe cannabis-derived medicinal products for patients with an "exceptional clinical need".

This means recreational cannabis use is still illegal, but it will be easier for cannabis-related products to be studied and prescribed.

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