The cost of medicinal cannabis has halved over the past year, but Australian patients are still paying 25 percent more than on the black market, a survey has found.

An increase in suppliers is bringing down the price of cannabis medications, with Australian patients now spending on average $370 a month for treatment, according to the market analysis released today by Cannabis Access Clinics.

But the amount paid by patients to relieve their symptoms can vary widely depending on the condition being treated.

Epilepsy patients are being hit with the highest costs, at around $1000 per month, while pain patients, who make up an estimated 60-70 percent of the market, are paying about $350 a month.

Lisa Johnson with her son Archer. The family are paying the equivalent of $40,000 a year for medicinal cannabis to treat his epilepsy. (Supplied)

Earlier this month, nine.com.au reported on the Johnson family in WA , who were being forced to sell their home to pay for the cost of treating their severely disabled and epileptic eight-year-old son Archer.

The high concentration of active ingredients required in Archer’s cannabis oil medication meant the family were paying $40,000 a year for his treatment.

NSW pensioner Warren Schell, 69, began taking medicinal cannabis in August to treat the severe pain caused by his osteoarthritis and osteoporosis, and said he had noticed “incredible” results.

“I had been suffering from chronic pain, 24/7 for 20 years. Now I don’t have any pain, it’s gone,” he said.

At a cost of about $300 a month, the treatment was difficult to afford on the old age pension but well worth it, he said.

Jannine and Warren Schell (Supplied)

“It costs a lot of money but if I want to be free of pain then I have got to have it. Which means yes, we have to readjust our lives and tighten our belts, but it’s certainly helped me and it’s gotten me in a better frame of mind.”

Cannabis Access Clinics operates a network of private clinics, with offices in Sydney, Melbourne and Brisbane and says it has “hundreds” of patients on its database.

The company collated the prices of the 11 suppliers who had medical cannabis available from the past 12 months to September this year and then compared them to what their patients paid.

While the price charged by suppliers was falling, the research found that the mark-up charged by pharmacies, who generally order in products from overseas countries such as Canada, could be as high as 140 percent.

No cannabis medications are subsidised by the Pharmaceutical Benefits Scheme (PBS), meaning patients are required to cover all of the costs.

“The pricing of medicinal cannabis products is still a contentious issue. As long as medicinal cannabis products are not covered by the PBS, it will appear expensive when compared to medicines that are heavily subsidised by the government,” the report stated.

Although several types of medicinal cannabis drugs are available through a Therapeutic Goods Administration (TGA) special access scheme, only one – used to treat multiple sclerosis in adults – has officially been approved by the body.

The TGA has so far approved 1442 patient applications for medicinal cannabis.

In contrast, the number of Australians thought to be accessing cannabis for medical reasons through the black market is estimated to be as high as 100,000.

In August, the University of Sydney published the results of its landmark Cannabis As Medicine Survey 2016

The survey of 1,744 Australians, completed in 2016, found many using illicit cannabis to treat chronic pain, mental health, sleep and neurological conditions like epilepsy or seizure disorders.

Researchers from the university are now conducting research for an updated 2018 version of the report.

“Little is known about how these tens of thousands of Australians – we believe in excess of 100,000 people – access cannabis on the black market, how they self-medicate and the conditions they are aiming to treat today," Professor Iain McGregor said, the study’s co-author, said.