Marina Spence has finally found a solution for her daughter Mikayla's debilitating epilepsy - she's just not sure how her family can sustain it.

"You've tried everything else and nothing else has worked," the Rossmoyne mother said.

Mikayla, 13, suffers from a rare disorder that causes multiple seizures each and every day... but medicinal cannabis has changed her life.

"She has a rare and complex neurological disorder and seizures are a very big part of that," Ms Spence said during an emotional interview with Gareth Parker on Radio 6PR's Mornings program.

"Another big challenge she faces from this condition is neurological irritability, which means she feels a lot of discomfort and sensory overload.

"Those two challenges present consequences that impact her every day life.

"So, when she's having seizures, it affects her cognition, her ability to concentrate, to learn, to communicate, and the irritability means she is feeling pain and discomfort pretty much a lot of the time.

"A typical day is a cycle between having seizure clusters, a little bit of calm and some irritability.

"On her worst days, which can extend out to months and months, she can cycle essentially from one to the other.

"So she can go from a high period of irritability - screaming, banging her head, trying to get the pain out - where everything that she does is uncomfortable.

"You can't touch her, you can't look at her ... noise, crowds, people around her ... it drives her crazy basically... and she just needs to be alone and in a quiet dark place.

"Then she'll go completely quiet, and the quiet means she's in a seizure... and so that essentially can happen all day, every day, so you can imagine the impact on her quality of life, having to endure that going on inside her head.

"You can imagine what people think when they see her as well, and quite often there are situations where she's been labelled as having bad behaviour because of the way her condition manifests, so it's quite humiliating to have that go on."

Medicinal cannabis will be dispensed to children in Victoria with severe epilepsy. Supplied

Regular family life just can't exist for the Spences ... reading books, watching movies, opening Christmas presents, family weddings, picnics... they basically cannot do if Mikayla is going through a particularly difficult time.

"The impact for her brother [aged 14] and his quality of life has been profound as well and as a family unit if you can't do those basic and essential things that bond a family together, of course it's going to have an effect," Ms Spence said.

"Our family bond has suffered and you can understand why families in situations like ours can end up breaking down because the pressure is so great."

Medicinal cannabis: A new hope

Effective treatments for Mikayla's epilepsy were non-existent before the medicinal cannabis road opened for the Spence family.

"In 13 years we have tried pretty much everything," she said.

"Essentially we were getting a whole bunch of side effects without much benefit.

"So that's why parents like myself will look to something because you've tried everything else and nothing else has worked."

Ms Spence convinced Mikayla's neurologist to submit an application to the Therapeutic Goods Administration for special access to MC, with a panel in Canberra determining whether the young teenager was worthy of access to the drug.

"It took several months to receive approval ... Mikayla's neurologist did infer it would be expensive, but I didn't have any idea of how expensive until I put the script into the pharmacy and was committed to buying it."

Only one supplier in Perth sells MC in oil form that contains no THC - the marijuana component that gives cannabis smokers a high - and 100 per cent CBD, the hemp part that provides health benefits to epilepsy sufferers like Mikayla.

Her family ordered three 25ml bottles initially and were hit with a $533 charge... per bottle, which usually lasted only six days - or $30,000 each year for the Spences to help their girl.

After starting "low and slow" with dosage levels for Mikayla, the effects were markedly more positive after a higher amount was administered.

It left the Spences with no choice but to continue down the expensive road so their daughter - and family as a whole - could live each day as close to a "normal life".

"She's been on it now for about four weeks ... as we increased the dose I could see an immediate change," Ms Spence said.

"She is still having some seizures but they have definitely reduced.

"What is happening now is, the time between her seizure cycles, she is a completely different person.

"It has helped with the severe irritability ... so she's no longer screaming, no longer trying to bang her head on her arms or legs or whatever she can reach.

"Her cognition has improved significantly, so she can focus, concentrate, read books, look at things, respond to your voice in a really timely manner ... there's no huge delay like there was before.

Mikayla has also been able to communicate more effectively with those around her, something that was blocked to her before.

"This is key to someone who can't speak using words," her mum said.

"It means they can make themselves understood ... and I can see her personality, her cheeky nature.

"She's actually enjoying herself, which she wasn't before, so her quality of life has been significantly improved."

Family life had also become much more happier in the Spence household.

"There's calm, everyone's relaxed, we can actually talk to each other, actually sit around the table and eat together... as opposed to us eating together and Mikayla eating somewhere else separately," Ms Spence said.

Given the current high costs of approved medicinal cannabis products in Australia, are they still a realistic option for an ongoing treatment program, especially for young people like Mikayla?

"Absolutely not," Ms Spence lamented. "And that's the dilemma.

"I had to try it because nothing else worked and we were desperate, and now we're in the situation where I'm thinking 'oh my gosh, it has had a significant impact, how on earth am I going to continue to pay for this'.

"And how can I actually let her go back to her life before this."

What does the future look like now?

Adult concoctions of medicinal cannabis are generally cheaper, as they contain some THC and require less processing to break down the marijuana components.

There are also more suppliers of these types of strains in Perth.

Dr Joe Kosterich, a medical advisor for Little Green Pharma, the Perth-based medicinal cannabis company awarded the first licence to grow and produce the product in WA, said prospective patients were realistically years from having cheaper access to MC.

Dr Joe Kosterich is an advocate for using medicinal cannabis to treat certain patients.

Those were generally epilepsy sufferers like Mikayla, chemotherapy patients who endure nausea and vomiting, or those with multiple sclerosis or chronic pain.

"We need more access ... the bigger the market, the more companies and competition we will have, and that will drive prices down," Dr Kosterich told WAtoday.

"It's not even an approved product yet, so each application requires TGA approval.

"To get on the PBS (Pharmaceutical Benefits Scheme), you then need a number of placebo-controlled trials in each area [MS, epilepsy, chronic pain and chemotherapy patients)."

Dr Kosterich said companies in these spaces were looking at opportunities to conduct trials ... "initially dosage regime, side-effect profiles".

But despite growing interest and awareness of medicinal cannabis as an appropriate treatment option for those with any of the four conditions, "big pharma" was not so keen.

"This is not your stock-standard medication, it's complex and not just about molecules, for example," he said.

"[Big pharma] also can't patent medicinal cannabis, like they can a vitamin."

Once companies in the industry had received TGA approval for their strains of cannabis, it didn't necessarily mean the product would be PBS-listed either, despite the success of similar ones overseas as a safe, simple and effective form of treatment.

"We're using a plant, an extract ... and we know what we're dealing with," Dr Kosterich said.

"We know it's safe for humans to take, we've seen evidence of its effect as a successful treatment overseas.

"It's now up to individual companies to get their product approved... then production will increase, we will need more harvesting, we'll start producing more and it will become cheaper to buy."

But in WA, this day is still years away, a gap that will feel like a lifetime for Mikayla Spence, her family and the many others in similar situations all across Australia.

So given the Spence's extraordinary dilemma, what does Marina see as the future for them and her 13-year-old daughter?

"I'm almost numb to it, I'm almost feeling like I will robotically go to the pharmacy and order the next script, and order the next script and put it in on the credit card and put it on the credit card and end up all of a sudden in a huge dire financial situation," Ms Spence told Parker's program.

"I almost can't think about it, because it's painful to imagine going back to what was before...

"I can't do that to Mikayla, and I can't do that to my son ... so I don't know."