THIS year the nation has been spirited back to 1914. Turn on a television or a radio, browse a news website or walk into a bookshop and up loom the ghosts of the Lost Generation, those millions who gave their lives in “the corner of a foreign field that is forever England”.

Every aspect of the First World War has been explored, its causes debated, the horrific conditions on the front revisited.

Yet less talk has centred on the psychological impact of trench warfare, which is why a new stage adaptation of Pat Barker's Regeneration adds to the sum of the centenary coverage. Barker’s novel was published in 1993 and there is still no shrewder or more moving account of shellshock.

Simon Godwin's production for the Touring Consortium Theatre Company and Royal & Derngate Northampton will visit York Theatre Royal from Tuesday to Saturday before its West End premiere in an adaptation by Nicholas Wright.

Unlike other much-loved novels from the Great War – Sebastian Faulks's Birdsong, say, or Erich Maria Remarque's All Quiet On The Western Front – Regeneration is a war saga in which not a shot is fired. Instead it is set in a psychiatric asylum in Edinburgh where the poets Siegfried Sassoon and Wilfred Owen received treatment from anthropologist Dr William Rivers.

Barker’s novel argues that it was in Craiglockhart, while cooped up with stammering and screaming veterans of No Man’s Land, that the older officer Sassoon helped Owen out of his chrysalis to become perhaps the definitive war poet.

This was one of the lures for the playwright Nicholas Wright, who had not read Regeneration – or the other two parts of Barker's trilogy – when he was asked to adapt it for the stage.

“Institutions always try to squash the individuality out of people,” says Wright.

“What’s so fascinating is how in this mental institution the men’s imaginations grow. The book very excitingly shows Owen discovering his talent, which comes out really over this vast crush he has on Sassoon because of the poetry. And how he learned his real metier, which was writing poetry about the war.”

The plays's central figure is Rivers, who applied the new-fangled teachings of Sigmund Freud to curing the shellshocked. As for Sassoon, he was wounded by friendly fire then sent to Craiglockhart in 1917 after denouncing the conduct of the war. Rivers’s task is to spare the Establishment’s blushes by proving his insanity.

This is all familiar territory to Wright. He has written many plays about historical figures including Van Gogh, Wallis Simpson’s lawyer, the broadcaster James Mossman and, most pertinently, the psychoanalyst Melanie Klein.

So he knows that the dramatic element to the patient-analyst relationship is made for the stage.

“The job of most plays – be they Hamlet or Lear or whatever – is for somebody to discover the truth about themselves,” he argues. “And it’s the same thing in analysis. But it wouldn’t be dramatic if it was an impersonal analyst helping the patient. They both have to be affected by it. It’s an interchange. And that’s the drama.”

So this is a tale from the trenches with a difference. For the director, Simon Godwin, the question still remains of how to stand out in a year of commemoration.

“The question in any kind of act of remembrance is how to make the memory live," he says. "What Nick has done is to take a story from the past but make it vividly alive to us now and that feels like it’s quite a different way of thinking about the First World War than simply trying to remember.”

Alongside the themes of poetry, trauma, class and honour, Regeneration explores repressed or unexplored homosexuality. Indeed of the main characters only the fictional working-class officer, Prior, is interested in women.

“One question in the play is about what is normal,and, as we know, deciding what is normal is as difficult now as it’s ever been,” says Godwin.

The director has assembled a young cast, with only Stephen Boxer as Rivers representing age and experience.

“Working with actors at the beginning of their careers only adds great poignancy to characters who have not had the chance to live the life that they hoped they would,” he says.

It also distances Wright's play from the 1997 film version, which starred Jonathan Pryce as Dr Rivers. Wright recalls the film as “heritage-y and polite”. He promises that his stage production will be anything but.

There is another twist to the play. With Pat Barker’s approval, Wright has raided The Ghost Road, the third novel in the trilogy, to bring the story of Wilfred Owen to a close. It’s hardly a plot spoiler to reveal that Owen did not survive the war, while Sassoon, according to Wright, “never really escaped it”.

“Wilfrid believed very strongly that there should be a poet in France so that the British public would know what was happening there and so that the men would have somebody to speak for them," he says.

"As far as Owen was concerned that was Sassoon. Then Sassoon got shot, leaving no poet there. That is one reason why Owen went out, leaving Sassoon with a mountain of guilt at Owen’s death. I wanted that to be part of the story, to make the play complete.”

Pat Barker's Regeneration runs at York Theatre Royal from Tuesday to Saturday, 7.30pm plus 2pm, Thursday, and 2.30pm, Saturday. Box office: 01904 623568 or yorktheatreroyal.co.uk

Jasper Rees. Additional reporting by Charles Hutchinson