What is cannabis oil?

Cannabis oil is extracted from the cannabis plant Cannabis sativa. The medicinal properties of the plant have been touted for more than 3,000 years. It was described in the ancient Egyptian Ebers Papyrus around 1550BC and was probably used as a medicine in China before that. Certain varieties of the plant contain high levels of the psychoactive substance tetrahydrocannabinol (THC), which is responsible for the "high" that comes from smoking or eating cannabis leaves or resin. The other major chemical component of the plant is cannabidiol, which has no psychoactive effect. Both act on the body's natural cannabinoid receptors that are involved in many processes such as memory, pain, and appetite. The cannabis plant also contains over 100 other different cannabinoid compounds in low concentrations.

So can cannabis oil make you high?

It depends on the THC content. Certain types of the Cannabis sativa plant, known as hemp, contain very little THC. The extracts of these plants mainly contain cannabidiol, so that no one will get stones.

Is this legal?

This is a complex question. Cannabidiol is legal in the UK. Extracts of the cannabis plant (known as hemp or CBD oil) are available in high-street stores, but the THC content must be less than 0.2 percent. "THC is not psychoactive at this stage," says neuropsychopharmacologist David Nutt of Imperial College London. But cannabidiol is illegal in many other countries.

For example in the United States, cannabidiol is classified as a Schedule 1 controlled substance, and can only be sold in states where cannabis use is legal.

However, the tide may be in favor of cannabis after a recent review by the World Health Organization. It concluded that cannabidiol "shows no effects of any abuse or dependence potential" but "has been demonstrated to be an effective treatment for epilepsy ... and maybe a useful treatment for many other medical conditions." "

Is there evidence that cannabis oil can help treat epilepsy?

Although there is some scientific evidence that THC has the ability to control convulsions, its mind-altering effects have meant that most attention has turned to cannabidiol—particularly for childhood epilepsy that conventional medicines fail to control. 

Two recent high-quality randomized and placebo-controlled trials have shown that cannabidiol is an effective treatment for Lennox-Gastaut syndrome and Dravet syndrome, severe forms of epilepsy. The mechanism of action is unknown, but it may be due to a combination of effects, such as inhibiting the activity of neurons and reducing inflammation in the brain.

When it comes to the use of commercial cannabis oil to control seizures, the situation is less clear, where the evidence is mainly anecdotal, and the oils may contain varying concentrations of cannabidiol 

The UK government announced on 19 June that it would review the use of medical cannabis.

Are there any cannabis-based epilepsy drugs on the market?

Not now. In April the US Food and Drug Administration recommended approval of a drug called Epidiolex for Lennox-Gastaut syndrome and Dravet syndrome. Its active ingredient is cannabidiol, and final approval is due later this month.

However, it's possible that the drug isn't as effective as cannabis oil containing THC, Nutt says. For example, cannabis oil was used to treat Billy Caldwell, the boy at the center of a recent cannabis oil seizure, with cannabidiol and low doses of THC, because cannabidiol alone could not stop all his seizures.

This is one of the great unknowns. "It is important to remember that there is currently little scientific evidence to support the use of both THC and cannabidiol as cannabis oil as a treatment for epilepsy," the charity Epilepsy Action said in a statement released this month.

Are cannabis-based medications available for other conditions?

Yes. A synthetic version of THC called nabilone has been used since the 1980s to treat nausea after chemotherapy and to help people gain weight. A drug called Sativex is also approved to treat the pain and cramps associated with multiple sclerosis. It contains an equal mix of THC and cannabidiol, but would not be suitable for treating children with epilepsy, such as Billy. "If you use it to treat epilepsy, kids' heads will hurt,".

Read more: Cannabis oil in India