Since the 1960s a disparate group of scientists and former drug addicts have been advocating a radical treatment for addiction - a hallucinogen called ibogaine, derived from an African plant, that in some cases seems to obliterate withdrawal symptoms from heroin, cocaine and alcohol. So why isn't it widely used?
For nearly 15 years, Thillen Naidoo's life was ruled by crack cocaine. Growing up in Chatsworth, a township on the outskirts of Durban in South Africa, he was surrounded by drugs.
After a troubled childhood and the death of his father, he turned to cocaine.
Though he held down a job as a carpenter and could go for days or even weeks without a hit, his wild drug binges often ended in arguments with his wife Saloshna and sometimes even physical abuse.
By the time he met Dr Anwar Jeewa at the Minds Alive Rehab Centre in Chatsworth, Naidoo had tried to quit several times and failed. "Those were dark, dark days," he says.
Jeewa offered a radical solution, a hallucinogenic drug used in tribal ceremonies in central Africa that would obliterate his cravings.
But Naidoo was anxious. "I didn't know what this ibogaine thing was," he says. "I never expected it to work."
After several medical tests he was given the pill.
A few hours later he lay in bed, watching flying fish swarm above his head. He felt the room move around him and a constant buzz rang in his ears. Scenes from his childhood flashed up briefly before his eyes and each time someone approached to check he was OK he felt a rush of fear.
The hallucinogenic effect wore off overnight but for the next few days Thillen was in a haze. When he returned home a week later, he realised he no longer craved cocaine. Six months later, he is still clean.
He attends a therapy group two days a week, where he learns the skills necessary to maintain a lifestyle without drugs.
"My mind has shifted now from what I used to be," he says. "I can look back at my childhood and deal with those issues without sobbing and feeling sorry for myself."
Jeewa estimates he has treated around 1,000 people with ibogaine but it remains largely unacknowledged by the medical mainstream.
The drug, derived from the root of a central African plant called iboga, had been used for centuries by the Bwiti people of Gabon and Cameroon, as part of a tribal initiation ceremony.
But it wasn't until 1962, when a young heroin addict called Howard Lotsof stumbled upon ibogaine, that its value as an addiction treatment was uncovered.
Lotsof took it to get high but when the hallucinogenic effects wore off, he realised he no longer had the compulsion to take heroin. He became convinced that he had found the solution to addiction and dedicated much of his life to promoting ibogaine as a treatment.
As far as scientists understand, ibogaine affects the brain in two distinct ways. The first is metabolic. It creates a protein that blocks receptors in the brain that trigger cravings, stopping the symptoms of withdrawal.
"Ibogaine tends to remove the withdrawals immediately and brings people back to their pre-addiction stage," says Jeewa. With normal detox this process can take months.
Its second effect is much less understood. It seems to inspire a dream-like state that is intensely introspective, allowing addicts to address issues in their life that they use alcohol or drugs to suppress.
Howard Lotsof's early campaign had little success and ibogaine was banned in the US, along with LSD and psilocybin mushrooms, in 1967.
In most other countries it remains unregulated and unlicensed. Lotsof set up a private clinic in the Netherlands in the 1980s and since then similar clinics have emerged in Canada, Mexico and South Africa.
These clinics operate in a legal grey area. But a small group of scientists is still working to bring ibogaine into the mainstream.
In the early 1990s, Deborah Mash, a neuroscientist and addiction specialist at the University of Miami, came upon the work of Dr Stanley Glick, a scientist who had researched the effect of ibogaine on rats.
Glick hooked rats on morphine, an opiate painkiller, by allowing them to self-administer it through a tube. He then gave them ibogaine and found they voluntarily stopped taking morphine.