WHEN heroin addict Brandon Garrison is asked whether he has ever overdosed, he is stumped.

His life has become so chaotic that he has to be reminded that yes, in fact, he came close to a fatal overdose just months earlier.

"Oh, yeah," he says in his distinctive Kentucky drawl, with a wry shrug at the camera.

Brandon, an addict of 10-12 years who started out started smoking cannabis before graduating to pills, cocaine and ultimately heroin, is one of four men featured in a new documentary that follows them as they try to kick their habit using neuro-electric therapy (N.E.T).

'The Final Fix', a film by Bafta- and Emmy-winning veteran Scottish director-producer Norman Stone and Glasgow-based 1A Productions, and narrated by 'Trainspotting' star Ewan McGregor, has already attracted the interest of streaming giants Netflix and Hulu.

Stone is due to fly to the US today for meetings in New York, Washington DC and Los Angeles as he bids to seal a distribution deal for the feature, which has been two years in the making.

His interest in N.E.T dates back to the 1970s, however, when the fledgling film-maker made a series of documentaries about it for the BBC and interviewed its inventor, the pioneering Scottish surgeon Dr Meg Patterson, who died in Lesmahagow in 2002.

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Now, with the US gripped by a spiralling opioid epidemic which has claimed more lives than the Vietnam war, and Scotland facing its own drugs deaths crisis, proponents of N.E.T believe we might finally have reached a "turning point" for a device which has been dismissed for decades.

The National Institute of Health, the US government's medical research body, is expected to commission clinical trials later this year and - as the Herald revealed yesterday - a Scottish university is in talks about setting up a multi-site study to investigate the potential of N.E.T as a rehabilitation tool.

Speaking to the Herald on Sunday, Stone said he was determined to approach the topic sceptically and "find a crack in the plaster".

He says: "I've got no skin in the game. I was committed to filming it as it happened, even if it had collapsed and failed. I'm not an N.E.T zealot coming at it in a biased way.

"But I am amazed, because it does what it says on the tin. The point, as we state at the end of the film, is 'well, shouldn't we look at this?' And we should.

"People are dying and the injustice makes me mad."

However, Stone adds that previous experience covering the issue left him disillusioned with the attitude of some medical professionals.

"In this city [Glasgow], I have been lied to by doctors who, when they see it, refute it.

"For the Scottish film that I did here, 'Coming Clean', I had a doctor lined up as the expert witness. He told me he wanted to be on TV - he actually said that.

"I said to him 'I want your honest opinion' but when he saw that it worked, he was off. He didn't want to comment on it."

N.E.T was developed in the 1970s by Scottish missionary surgeon, Dr Meg Patterson, while she was working at a charity hospital in Hong Kong.

She made the chance discovery while trialling a Chinese technique of electro-acupuncture on patients who happened to be hooked on opium - although Dr Patterson did not know this, and the original experiments were not focused on addiction.

However, the participants subsequently told Dr Patterson that the treatment appeared to have wiped out their desire for the narcotic.

Dr Patterson set aside her own scepticism and concluded that it must be the electrical currents, not the acupuncture needles, which was having some effect.

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She spent the rest of her life devoted to N.E.T, garnering plaudits from rock stars including Eric Clapton and Keith Richards, who credited the technology for their recovery from addiction.

HeraldScotland: Eric Clapton and Keith Richards credit N.E.T for getting them off drugs Eric Clapton and Keith Richards credit N.E.T for getting them off drugs

The treatment claims to work for everything from nicotine to alcohol and every form of drug dependency, from prescription painkillers to cocaine and heroin.

It uses a device, only slightly larger than an MP3 player, with tiny electrodes taped just behind participants' ears.

The N.E.T machine is then calibrated to send low-voltage electrical pulses - adjusted depending on each individual's addiction - into the brain.

The theory is that it works by accelerating the brain's own natural repair process, enabling it to respond normally again to endorphins - the body's stress and pain-relieving hormones - which is disrupted by long-term abuse of drugs.

HeraldScotland: The N.E.T device The N.E.T device

At the time that Dr Patterson first stumbled on the phenomenon, however, endorphins had yet to even be discovered.

That was also a Scottish breakthrough, 1976, by Hans W. Kosterlitz and John Hughes at Aberdeen University.

The effect, it is claimed, is a faster recovery time without the usual nasty withdrawal symptoms such as severe stomach cramps, loss of appetite, vomiting, diarrhoea, insomnia, and restlessness, as well as a reduction or elimination in cravings long-term.

It sounds too good to be true - and plenty think it is - but the documentary seeks to present an honest account of those experiencing N.E.T first-hand in a trial at the Isaiah House drug withdrawal facility in Louisville, Kentucky.

The four addicts - Brandon Garrison, Kevin Arnold, Robert Capley and Ross Smith - have all previously tried and failed to quit heroin or suboxone (the American version of methadone), but some have additional addictions such as amphetamine.

Kevin says he found the “pain and discomfort too much” during previous detox attempts, while Ross says he lasted six days but "it was impossible".

Kentucky has one of the worst drug death rates in the US, with some 30 residents a week fatally overdosing on pharmaceutical or illicit opioids.

A fifth addict featured in the documentary, David Emanuel, turned to heroin after becoming hooked on opiate-based painkillers prescribed when he was hit by a car.

Tragically he is kicked off the trial after smuggling drugs into the rehab facility and is later found dead from a heroin overdose. The film is dedicated to him.

The difference is evident in week one as the trial participants, hooked up to their N.E.T devices, talk of sleeping through the night without sweats or chills, very little or no pain, no diarrhoea, no nausea, and a general sense of calm.

They describe "zero" cravings for drugs, and are seen tucking into hearty plates of pizza and chips at lunch or playing ping pong.

Dr Quinn Chipley, a medic and psychologist from Beacon House, a Louisville drug and alcohol facility, visits the trial as a sceptical observer.

“We have people who are only two to three days in and they are not reporting feelings of dysphoria," he says. "They don’t have diarrhoea, no vomiting, big appetites, much earlier than we would expect. I find that to be really astounding.”

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Matt LaRocco, another impartial onlooker from Louisville's syringe exchange program, adds: "I’ve never seen anything like this. For the variety of drugs and the amount they were using, I’ve never seen anyone doing this good after seven days.”

By the end of the two-week detox - it would normally take 21 days - all four men are clean.

HeraldScotland: Robert Robert

Remarkably, one of them - Robert - is arrested for prior misdemeanours two days after leaving Isaiah House and spends next three months in the local prison - nicknamed the "drug supermarket".

When he is released on parole, however, urine tests reveal he is clean of drugs.

"110 days sober and no cravings," he says.

Brandon - who started out unable to even recall his own recent overdose - is seen eight months later, meeting with Ross and Kevin for lunch.

All three remain free from drugs with Brandon now studying engineering and "top of his class".

It sounds like a miracle cure. So why hasn't N.E.T been seized on before now on both sides of the Atlantic?

“No one can work out how to make money out of it,” says Mark LaPalme, founder and CEO of Isaiah House.

The documentary opens with clips from pharmaceutical company info-mercials from the 1990s where viewers were reassured that long-term use of powerful opioids such as oxycontin was completely safe and “less than 1% of patients become addicted”.

In the interim, drug deaths in the US have soared from fewer than 6000 in 1998 to 72,000 by 2017, the vast majority of them caused by legal and illegal opioids.

The contention as to whether pharmaceutical giants knowingly harmed consumers by pushing addictive prescription drugs in pursuit of profit is at the centre of hundreds of lawsuits currently being brought across the US as city and regional administrations seek damages for the havoc the pills have wreaked on their communities.

It is clear that 'The Final Fix' - and Stone himself - agree with LaPalme's take: that the pharmaceutical industry, which bankrolls so much of medical research, is not interested in backing a non-pharmaceutical, potentially one-off therapy.

Where would be the money in curing people once and for all?

Joe Winston, the CEO of NET Recovery Corp and son-in-law of Dr Patterson, adds: “In the early days, I believe there was a national resistance to medication based on electrical stimulation.

"Today, I think it’s rejected for a very different reason. There’s substantial business in the treatment of opiate addiction.”

HeraldScotland: Owen Fielding and Myrrh Winston during the Kentucky N.E.T trialOwen Fielding and Myrrh Winston during the Kentucky N.E.T trial

Myrrh Winston, an ER nurse and Dr Patterson's daughter, says she believes it was the "massive stress" of trying to have N.E.T taken seriously in her lifetime that contributed to her mother's stroke.

She remains pessimistic that her mother's vision will ever be realised.

“She kept pushing and pushing but there was always one more hurdle, always one more trial, another $10m needed," says Winston.

Owen Fielding, the Scotland-based director of clinical services for NET Recovery Corp, says their own in-house studies in Scotland and Kentucky demonstrated significantly reduced withdrawal symptoms in 80% of the 552 participants, with 92% reporting that it had substantially eliminated their cravings.

"That's on a five to seven-day, one-off treatment with no need to repeat," said Fielding.

"The brain has 'plasticity'. If you lock an addict in a room for a few weeks they might come out with cravings still, but essentially their brain would be restored to normal.

"What we are doing with N.E.T is accelerating that process."

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Results from other academic studies have also been promising.

A 2012 analysis of 104 methadone and heroin users treated with N.E.T at six residential facilities in Scotland found a "statistically significant decrease in both craving and withdrawal symptoms".

At six months, abstinence rates were 61% - compared to 40% normally seen post-detox - and treatment outcomes were rated "as good or better" than standard pharmaceutical-assisted regimes.

However, other studies have been more muted in their conclusions.

A 1992 randomised, double-blind placebo trial - the gold standard methodology for research - compared 18 opiate-dependent and 25 cocaine-dependent volunteers on NET and a placebo version of NET with almost negligible current.

Researchers at the University of Pennsylvania's Centre for the Study of Addiction found "no significant difference between the active or placebo groups" in terms of withdrawal symptoms or cravings.

So is N.E.T a case of mind over matter?

"Even if it were a placebo effect, that's still a pretty good result," says Stone.