Relief of pain, nausea, anxiety, spasticity -- medical cannabis claims to help with all these and is particularly useful for cancer and MS patients. So, should it be legalised?
Irishman Gordon McArdle knows the Californian health system well. He operated a medical marijuana dispensary in Napa Valley and later on was prescribed medicinal marijuana, or cannabis, for post-traumatic stress disorder which he continues to use for the condition.
Now living in Dublin, Gordon (36) is conscious of the disparity between the drug laws in California and Ireland, where any use of the drug is completely illegal, even for the relief of pain and other chronic conditions.
He is also at the forefront of a campaign which those involved hope will one day see people here taking the drug, free from the fear of arrest or prosecution.
In California, he had an ID that permitted him to purchase cannabis for medicinal purposes and he could go into a special dispensary to get it. In Ireland, he can be arrested and prosecuted for possession of it.
It's now 15 years since the people of California voted to legalise medical marijuana for those with relevant health conditions. Just last November, the US state almost became the first to completely legalise marijuana until the proposition was narrowly outvoted.
The Californian approach to medical cannabis is seen as progressive. It is also highly regulated and brings in some much-needed income to California's depleted state coffers, through a fee that people pay for their ID cards.
"The EU has laws which say you cannot deny somebody something that would make their lives easier," Gordon says.
"We need to start to push the Government, in the courts if it comes to it, in order to have that right. People have legitimate reasons why they want to use cannabis for medicinal purposes but they are being forced to become criminals in this country because of the way the law stands."
Under the Misuse of Drugs Act 1977, cannabis and cannabis-based medicinal products are Schedule 1 controlled substances.
This means they are considered to have no medicinal use and it's illegal to "manufacture, produce, prepare, sell, supply, distribute or possess cannabis products except for the purposes of research".
Last September, the Department of Health and Children confirmed that it was seeking expert advice with regard to the act and this review is still ongoing.
A spokesman said: "The department is aware that claims have been made in respect of the possible health benefits of cannabis-based medicinal products for patients suffering from certain conditions such as Multiple Sclerosis, and is also aware that cannabis-based medicinal products may be legally prescribed in certain other countries."
In Ireland, there are two main approaches to the issue -- those people who want an outright legalisation of cannabis and those who prioritise the legalisation of medicinal cannabis.
Legalise Cannabis Ireland says it has decided not to divide the issue at the moment because it says that some people could be using cannabis recreationally and not be consciously aware that it's treating an underlying health issue.
However, Gordon McArdle says, "I wouldn't be against legalising it outright but I would say that for people to expect that to happen is unrealistic. My primary aim is for patients who want to be able to use cannabis for medicinal purposes -- the cancer patients, the people who are seriously ill."
Research studies of cannabis show it can play a role in treating conditions such as Multiple Sclerosis, HIV/AIDS and chronic neuropathic pain. Its main function appears to be relieving nausea, pain, anxiety and spasticity in the body's muscles (a common symptom for Multiple Sclerosis patients).
Despite its illegality, there is significant use of the drug in this country. It's estimated that one in six people have used cannabis during their lifetime and it's thought to be the most widely used illicit drug in the country.
It's not known how many Irish people are currently using the drug for medicinal purposes and there is a lot of secrecy and stigma surrounding the issue, given the risk of being arrested for using it.
Frank* is a grandfather in his 50s who has been using cannabis for years to relieve his Multiple Sclerosis symptoms.
"I did an awful lot of football when I was younger and then I started falling over around 15 years ago," he says. "One side of me was like a young fellow and the other side was like an old man. They told me in 2000 that I had MS.
"I was given medication but I found that I was getting sick with the tablets. When I started to use cannabis, I got a lot of pain relief and my nerves got better. If I don't have a smoke, I get very annoyed with the pain.
"I told a doctor once that I used cannabis and the next day, the guards came up and took away the plants I was growing."
Frank, who walks with a cane, now buys cannabis and says his family are aware of it but he doesn't let anyone else know for fear of the stigma it might bring on his family.
William Geraghty, from Meath, was diagnosed with Acute Myoblastic Leukaemia in 2002 and faced a course of chemotherapy. To cope with the symptoms of the chemotherapy, he took cannabis. He openly talks about his experience as he is an advocate for cannabis becoming legal.
"I smoked cannabis to help me get through the chemotherapy," he says. "I've seen people get sick after chemotherapy and I think it kept me going. I never once had a negative side effect from the cannabis.
"I think the medical staff was aware that I was using it as I did mention it. They couldn't talk about it with me, of course.
"I've met many people over the years that've used it for various reasons. I think people are curious about it but afraid to talk about it openly."
While some health benefits of cannabis have been pointed to in research studies, some questions are regularly raised about the use of cannabis.
It is stated that it's a gateway drug, is addictive and has side effects such as causing depression or anxiety.
Darcy Petticrew, of Legalise Cannabis Ireland, says that there's no clear evidence of cannabis being a gateway drug and cannabis in itself isn't addictive.
"The fact that some people mix cannabis and tobacco together to smoke it means that they become addicted to the nicotine," he says. Opinion on the addictiveness of cannabis is divided with arguments on both sides.
Gordon, who is originally from Monaghan, narrowly missed out on getting enough signatures to run as a candidate in Dublin North-West in the recent general election. He says the argument that cannabis has side effects could equally be applied to pharmaceutical drugs.
"There are side effects to every pharmaceutical drug out there. When I get a box of anti-depressants, it says on the side that this could cause you to have suicidal thoughts. If you can find one drug that doesn't have side effects, you can go ahead and use that argument. Otherwise, labels could be put on a bag of cannabis if it was sold in a dispensary.
"The fact is that the biggest harm that cannabis does is create crime.
"The other states in Europe have had a common sense approach to the issue -- it's time we had a common sense approach to it. We should legalise cannabis for medicinal purposes at least and take the revenue away from criminal gangs."
Gordon drafted a law last autumn and presented it to Pat Carey, the then Minister for National Drugs Strategy.
"The Compassionate Use of Medical Cannabis Act gives the Government a framework for how to do this, in terms of GPs recommending patients and them then getting an ID card," says Gordon.
"It would be closely regulated in terms of that person being able to go to a state-monitored medical cannabis dispensary to get their prescription filled.
"There is a lot of scientific research out there on the subject and I've 1,200 documents that I've offered to the Government for their information. There is also a lot of evidence from seeing how it's helped patients first hand and their voices are not being heard.
"I don't want this to be something joked about in college dorms or the likes of that. I want this to be something where people look at this and say this is a serious health issue."
* Not his real name
By Lisa Jewell