John puts The Passion of the Christ soundtrack on the stereo and lies on the single bed in this Melbourne house.

He's a 37-year-old engineer working in the renewable energy sector, and not at all savvy about street deals, so he bought his dose of cactus, which contains mescaline, on the dark web.

He takes it without ceremony, then talks to his therapist about how he's been feeling. When he starts to feel a vague effect of the drug in his thighs, John puts on his eye shades and waits for the first wave to hit.

This is underground psychedelic psychotherapy, using illegal substances and facilitated by therapists known only through cautious word of mouth.

While most people are unaware it exists, it's been going on globally since the 1950s.

That's when clinical trials into the possible uses of psychedelics began, before being curtailed by LSD being made illegal.

Now trials are underway again, in the US and UK in particular, including using MDMA (not strictly a psychedelic) for PTSD, LSD for anxiety, psilocybin for depression — and advocates believe it could transform mental health care.

The most optimistic researchers hope that regulated psychedelic-assisted therapy will start rolling out slowly in 2021 with approval from bodies such as the FDA.

But not everyone wants to wait, or to be dictated to by government bodies and pharmaceutical companies.

What happens in an underground session?

John is in his 11th year of treatment, which has included holotropic breathwork and regular psychoanalysis.

"When I started I was on the brink of suicide," he says.

"It stems from sexual, physical and emotional abuse when I was two to three years old."

A hypnotherapist referred him to a therapist known for treating trauma. John had no idea that his new therapist facilitated psychedelic sessions.

"He uses whatever works for the individual," John explains.

"It might be talking therapy, meditation or relaxation techniques. Given I'd had recreational experience with psychedelics, it's something he put forward."

With the aid of psychedelics, John says he can access memories quicker than with regular therapy.

A session costs $150 an hour — there are obviously no mental-health plan rebates — and can last anywhere between 30 minutes for DMT, to five hours for MDMA and 14 hours for mescaline.

The hard work comes in the ensuing sessions, when he and the therapist integrate what he experienced during the trip.

As John points out, it's far from fun. He's concerned that news stories about trials make out psychedelic psychotherapy to be a quick fix.

On TV show The Doctors, for instance, a woman who took part in a clinical trial of MDMA-assisted therapy claims her PTSD was "cured" in three sessions.

Quality control could fall by the wayside

Dr Prashanth Puspanathan — who goes by Dr Prash — is a medical doctor and neuropsychiatry fellow at The Alfred Hospital, Melbourne.

Four years ago he gave his first talk to the Alfred's psychiatry department about advances in psychedelic-assisted psychotherapy, and he's impatiently awaiting regulation.

"I don't plan on being in conventional psychiatry for the rest of my life," he says. "The psychedelic sphere is where I see promise for the future."

Dr Prashanth Puspanathan is impatiently awaiting regulation. ( Supplied )

Dr Prash can understand the rise in underground practice.

"The more that the Australian population reads stories about trials in other parts of the world, the more they'll get frustrated at the lack of access," he says.

His concern is that anything forced underground becomes adulterated.

"We saw that with prohibition in the 1920s and the war on drugs in the current day," he says.

"In the case of medical cannabis, regulation took ages, and by that point people thought, 'I'll just give my child cannabis.' But you're not necessarily going to choose the right compound for the right problem."

Legal consequences of underground sessions not clear

Facilitating underground sessions is risky for therapists, particularly if they're registered with the Australian Health Practitioner Regulation Agency (AHPRA).

Technically they're not breaking the law because they're not supplying the substance, but if something went wrong it's not clear what the legal consequence would be.

Ethically, it could be argued that they're not acting in the best interest of their profession just by being there.

"If you were called up to the medical board or the health practitioners board of AHPRA then you would be judged by your peers about what is considered to be a good standard of care," Dr Prash explains.

A spokeswoman for the Psychology Board of Australia, which operates through AHPRA, says: "If a practitioner is placing the public at risk, National Boards and AHPRA would want that concern raised with us.

"Psychologists must only provide psychological services within the boundaries of their professional competence.

"This includes working within the limits of their education, training, supervised experience and appropriate professional experience; basing their service on the established knowledge of the discipline and profession of psychology, and complying with the law of the jurisdiction in which they provide psychological services."

It's risky for patients too, who place a lot of trust in their therapist. In California, six women accused the founder of the Interchange Counseling Institute of sexual assault after taking hallucinogens.

Patients with a family disposition towards psychosis would likely be discounted from regulated psychedelic psychotherapy, but these precautions are not guaranteed with underground sessions.

Similarly, some medical conditions are prohibitive: in 2014, West Australian man Brodie Smith died in a Thai rehab centre when having his methamphetamine dependence treated with ibogaine.

Then there's the issue of — in psychedelic circles — seasoned "trip sitters" upgrading themselves to therapists and tackling a friend's trauma.

"That's one of the biggest problems," Dr Prash says.

"They might measure the dose by what they've read around clinical trials, but the purity of street MDMA could be 20 per cent. Other adulterants potentially include meth."

Dr Prash thinks that even if the TGA approves psychedelic psychotherapy in Australia, the earliest clients are likely to be from the severe end of the spectrum, such as end-of-life patients who might be treated by psilocybin.

"That's the first area that stigma recedes from," he explains.

"There's an 'ah, why not?' attitude from the public, which influences policy makers."

The efforts to get trials approved in Australia

Some medical professionals and researchers worry that unsanctioned practice will jeopardise regulation later on.

Dr Nigel Strauss advocates for clinical trials to be held in Australia. ( Supplied )

As psychiatrist Nigel Strauss points out: "If there's some terrible outcome where someone dies or develops psychosis, that's bad news for the rest of us trying to initiate scientific studies."

Dr Strauss has a long interest in PTSD, having worked with the survivors and families of the Port Arthur massacre and the Black Saturday bushfires.

"I'd always thought that the available treatments were not really adequate," he says, "so I had a look at the evidence that was coming out of MAPS [the Multidisciplinary Association for Psychedelic Studies in the US] and was impressed by the early results."

He now advocates for clinical trials to be held in Australia.

He and Dr Martin Williams of Psychedelic Research in Science and Medicine put in a submission to Deakin University in December 2015 for a PTSD study using MDMA.

It was blocked at the last moment by a professor who worried that the research would attract adverse media coverage.

"These drugs are stigmatised and there are frequent headlines about young people overdosing in clubs on ecstasy," Dr Strauss says.

"Universities are fragile places: they're financially dependent and under pressure.

"It's a generational thing as well — I think if the people making the decisions were 30 years younger, we might have more hope."

Evolving a new system

Trials are underway, in the US and UK in particular, including using MDMA for PTSD. ( Unsplash, file photo )

Dr Strauss thinks trials will begin in Australia in the next five years, but acknowledges the difficulty of trying to shoehorn the countercultural phenomenon of psychedelic use into the paradigm of science.

"It's up to scientists and psychiatrists who have an understanding of consciousness to find a way," he says.

"I'm interested in evolving a system where there could be more synergy between the two."

Ben Sessa is a Bristol-based medical doctor already carrying out MDMA trials to treat alcohol dependence.

Dr Ben Sessa is fairly sympathetic to underground psychotherapy, having been a raver in a past life. ( Supplied: drsessa.com )

In a past life he was a raver and a club DJ, so he's fairly sympathetic to underground psychotherapy.

"There's a massive amount of knowledge within it so it's not to be sniffed at," he says, "because anecdotally the experiences can direct researchers to new avenues. But it's not going to help getting new drugs licensed. That has to be done in the way that the regulatory authorities want you to do it, based on studies."

Dr Prash has a similar view.

"If it's underground then it doesn't have the kind of vigour that the mainstream scientific model requires, and then it's not going to get much purchase anywhere," he explains.

"It would be no more useful than the anecdotal evidence that we're all already aware of. It can't be peer reviewed and the validity of your results cannot be assessed."

In decades to come, perhaps we will see the MAPS vision of psychedelic centres that aren't restricted to people tackling mental health issues. But in the near future, progress will be slow.

John is concerned that certain drugs will be mandated for certain conditions, as if one size fits all. He also wonders how client-practitioner boundaries will be flexible enough.

"This isn't an hour-long session where the therapist says, 'Time's up,'" he says.

"Sometimes afterwards I won't feel good so I'll hang about until I feel safe."

Dr Sessa acknowledges: "Quite a lot of people say to me, 'Why do you bother trying to license these drugs? There are plenty of good underground therapists' — and that's true.

"But there are 70,000 untreated cases of PTSD in the UK, and the majority of those people don't want to break the law.

"They're the population that I'm interested in increasing access for, so you have to beat the man at his own game."

Jenny Valentish is a freelance journalist and author of Woman of Substances: A Journey into Addiction and Treatment.