He's back at the hotel in Nice, where he was a shift worker, on July 14, 2016.

"Suddenly I hear cries ??? a human tide rushes inside the hotel uttering screams of fear??? in a brief moment everything turns to horror.

"I am traumatised to see and hear the cries and tears of the children around me. I see the wounded that are beginning to arrive [with] open wounds, fractured limbs or the head covered with blood. I am horrified and annihilated by this vision. I am completely overwhelmed and destitute by these events. I am lost, and I begin to be disoriented.

"In the entrance hall, someone has just arrived with the body of a child. His head tosses in the void."

For the past month Max de Rekeniere, 56, has visited a Nice hospital and taken two white pills, swilled down with a glass of water. He has then written down his trauma, in the present tense, recalling all the events and feelings from the terrible heart of the Nice terror attack as if they were happening again, and he was feeling them again.

And then he has read his account to a psychiatric researcher as part of a trial of a ground-breaking new treatment that hopes to "cure" - or at least help treat - post-traumatic stress disorder.

Inside de Rekeniere's brain, goes the theory, the drug Propranolol is policing his synapses. It is believed that memories, once laid down, are not immutable. When they are recalled they must then be "reconsolidated", stored back to memory like a library book returning to a shelf. But Propranolol inhibits this reconsolidation process.

This is not an Eternal Sunshine of the Spotless Mind scenario. It's not like the memory is erased. But it is [hopefully] dulled, drawn of venom and immediacy.

More than 80 people were killed and dozens more injured in Nice when a truck deliberately drove into a crowd celebrating Bastille Day. Many more were left traumatised. And some, like de Rekeniere, are still crippled by PTSD.

Terror attacks leave a cruel, lingering penumbra of mental harm. Three months after the Paris attacks of November 2015, more than 1000 people had sought psychological support.

According to an article in The Lancet in July, one third of people involved in a terror attack either as direct victims, their families, or the first responders are likely to develop PTSD. Of those, one third will not have recovered after 10 years.

De Rekeniere says he began to feel "broken inside".

"After a few days everything collapsed in my life. It's like I was in the dark for three months. I don't have the possibility to talk. I was very, very bad."

He couldn't work. Still today he doesn't like to go into the city of Nice. He fears crowded streets. When the sound of summer fireworks reaches his home from the coast he can feel himself tensing up.

Vivid nightmares, night after night, drag him back to scenes he wishes he could forget.

And perhaps Dr Alain Brunet can help him do that.

Brunet is a Canadian expert in PTSD, who for several years has been developing a new treatment using Propranolol.

In late 2015 he was getting excited about data from a trial, formally published this year, which had extremely promising results in humans.

And then terrorists rampaged through central Paris.

"I have a number of acquaintances there, the events really impacted me," Brunet says. "So I started contacting friends and colleagues over there and said to them: 'We really need to do something [about] all the suffering'."

He proposed a new trial of his technique. He flew to France and presented it to the authorities and - eventually - won approval and funding.

Since last June they have treated 175 patients, from the Paris and then the Nice terror attacks, using his method. In the year that the project has still to run, he hopes to recruit around 300 in total.

Brunet explains that a memory blocked from reconsolidating will be "perhaps not forgotten completely - that's not the result that we're getting - but some components or some aspects of it will be degraded".

"We're interested mostly in the emotional component of the memory. Recalling a memory under a reconsolidation blocker [means] the memory is less emotionally intense."

In his early animal research they found they could block memories in a single session. In humans it sometimes works that quickly. But for memories that are extremely traumatic, to obtain a strong clinical result they need to do it six times.

So people like de Rekeniere, once a week for six weeks, take the drug, write down their nightmare then recite it.

Brunet says the beauty of the treatment is not just that it works - there are other treatments, particularly cognitive behavioural therapy (CBT) that work well.

But CBT requires a lot of expertise, it's a sophisticated treatment, he says, that requires years of training. His method can be taught to any clinician - and in the case of a mass attack that left hundreds or thousands traumatised, it could be widely and quickly deployed.

"We are still collecting data," he says. "It's obviously difficult ??? but [CBT] treatment involves talking about your trauma, there's no way around that. So the treatment we propose is not more difficult than any other but it's much shorter.

"Generally by the second or third treatment session they already see a difference and by the fourth treatment session very often they will sometimes say, 'I am reading this scenario, I am reading this script and it feels like it happened to someone else'.

"It's quite a powerful experience to witness. I am completely thrilled by it."

Dr Jennifer Wild is a clinical psychologist at Oxford University, researching memory, PTSD and anxiety disorders.

She says the treatment that works best for PTSD is trauma-focused CBT - in her experience about 80 per cent of patients recover within six to 12 weeks.

She says understanding memory is the key to understanding PTSD.

"It's the worst moments that usually come back to mind rather than a complete narrative of the event," she says. "The way people think about the trauma and its aftermath also leads to a sense of current threat."

People with PTSD are unable to learn that they are safe again. Because of the nature of the memory and the way they think about it and react to it, it is as if they are trapped in their terrifying past.

So trauma-focused treatments, says Wild, seek to "elaborate" the memory, updating it with new information.

They actively try to trigger the trauma memory, to help patients discriminate between what's the memory and what's going on now.

"When they get to that point in the trauma where they're talking about what happened and they have the thought that 'I thought I was going to die', we would then have them say 'and now I know I didn't die, I'm safe, I still see my kids'. So the memory gets updated."

She says the Propranolol approach is "an interesting one" - though she has reservations.

"While Propranolol may block the recurrence of the memory it doesn't actually change the meaning for somebody, which is what our trauma-focused treatments are doing," she says.

"So if you reduce the memory you're not going to necessarily change the meaning. I'd be really interested in these trials once they have results, it'd be really interesting to look at."

Wild is not the only person to express reservations about the use of Propranolol in modifying memory.

In 2009 a team from the University of Amsterdam made worldwide headlines with a study in which they used the drug to apparently "cure" arachnophobia, by eliminating the fearful response associated with images of spiders.

At the time, the mental health charity MIND issued a statement saying it was "fascinating research that could transform the treatment for phobias and post traumatic stress disorder".

But they added: "We should also exercise caution before heralding this as a miracle cure. Eradicating emotional responses is clearly an area we would need to be very careful about.

"It could affect people's ability to respond to dangerous situations in the future and could even take away people's positive memories ??? we would need to see much more research into the risks and benefits of this treatment before it becomes a reality."

Brunet's technique is not the only new PTSD therapy to come to light recently. Scientists in Japan are developing "fMRI decoded neurofeedback", which uses a computer to analyse brain activity in real time, and tries to find moments when fearful memories are activated so they can be "overwritten" with a reward.

In this way, patients needn't even recall their trauma in order to have it dulled. However, the technique is at a very early stage of development.

In Australia, earlier this year the Centre for Posttraumatic Mental Health at the University of Melbourne announced a new trial of an intensive PTSD treatment program, recruiting current and former Australian Defence Force members.

That program involves an intensive, two-week period of treatment, which the researchers believe may provide equal or better mental health outcomes than current 10-week therapies.

Chief investigator Professor David Forbes says even the best PTSD treatments available were not a solution for everyone.

"We need to develop and test new and innovative approaches to help those not benefiting from current approaches," he says. "The outcomes of this trial will help not just the military and veteran community, but also other Australians with PTSD as we improve PTSD treatments for everyone."

Rick Corey is a close friend of de Rekeniere. Though they live on different continents, they talk almost every day.

He says that before the Nice attack de Rekeniere had been "an adventurer". He had saved up money working as a butler in Paris, Monaco and London, and was "like a tiger in a cage" waiting for the next opportunity to travel.

But when they spoke after the attack "he was crying like I heard no one cry before", Corey says. "Max was not to be the same, maybe ever again."

Corey heard from de Rekeniere after each of the treatments from Brunet's program.

After the first session, "Max told me that he cried the whole time".

After the second "he told me that it felt like someone took a knife and pushed it into his stomach".

But after the fourth, last week, Corey believes "Max was a lot better. To me at least".

"He talked more freely. He listened to me. He was concerned for me and my feelings.

"My friend Max was coming alive again."

De Rekeniere is not sure.

He leaves each session tired, he says - "it is full of stress for me to do that, because I have to repeat the story over and over".

But he thinks it is a good treatment. He has tried other therapies, but they did not help. He was put on anxiety medication that had "horrible" side effects - it made his body shake and he found it hard to sleep or pee. This drug has no side effects that he can see.

And maybe he is starting to feel better.

"It's difficult for me to explain, my mood is still up and down. But I feel something changed. Like my nightmares, and my sadness. It's different."