Post-traumatic stress expert

He said: “You hear how huge the impact is, even for people who weren’t actually injured, and how they experience dissociation for quite a while afterwards, perhaps seeing everything as unreal, or looking down on themselves from a distance.

“There was one person who years afterwards was in a nightclub with low lighting and lots of people from his work and suddenly he couldn’t remember anything. The next he knew he was outside on a bench with medics around him.

“Eventually he saw a therapist who could reassure him and he realised what was happening and that the nightclub was a bit like the underground.”

Dr Marzillier’s memoir, The Gossamer Threat, uses dozens of case studies to tell the story of how he became a clinical psychologist, a naive believer in scientifically-based behavioural therapy, but gradually moved to retrain as a psychodynamic psychotherapist.

During the 37 years of his career, treatments changed dramatically. When he arrived to study psychology and philosophy in 1964, Oxford was in the grip of behaviourism — explaining human behaviour by showing how rats moved in response to rewards of food.

He went on to qualify at the Maudsley Hospital in London, treating phobic clients with aversion therapy. He describes Gary from Chipping Norton, whose hands were sore from obsessive hand-washing, who was threatened with a frontal lobotomy, a brain operation made famous by Jack Nicholson’s film One Flew Over the Cuckoo Nest.

He writes: “There is no going back once the bit of brain is removed and the outcome is pretty uncertain. The doctors are happy for us to experiment.” The young psychologist dips his own hands in the flower bed, encouraging Gary to do the same, dirtying his hands, face and neck, and ordering him not to wash until 6pm.

In 1982, Dr Marzillier moved to the Warneford Hospital in Oxford, where he trained in the then new technique of cognitive therapy, which combines behavioural training with challenging people’s negative thoughts. Working with a GP in Thame, he sees a client called Naomi, who says that a friend ignored her in the street, a fact she interprets as meaning that the friend finds her boring. The therapist challenges this, suggesting that perhaps the friend just didn’t notice her.

Dr Marzillier said: “I immediately felt there were limitations to this approach. While cognitive therapy is very good at picking up thoughts of failings that come into people’s minds and trying to change them, it didn’t seem to change more fundamental beliefs that people have like ‘I am a hopeless person’ — the thoughts that people get when they are very depressed.

“You can’t tackle fundamental beliefs with rational arguments, because they aren’t rational. They are emotionally based.”

So, at the age of 44, Dr Marziller went back to the classroom, taking a part-time course at the Warneford to train as a psychotherapist. His interest spread to literature, his thesis topic being Oscar Wilde’s Portrait of Dorian Gray as a description of a narcissistic personality.

He has since taken a creative writing course and completed two unpublished novels, several short stories and poems. The Gossamer Thread — the title refers to the fragile link between client and therapist that he believes lies at the heart of successful treatment — started life as a novel. Having turned it into a semi-fictional memoir, Dr Marzillier, 64, has moved to his next project, a firmly factual book about trauma, inspired by a survivor of the Paddington train crash.

“You go about your life, travelling on a train to work on July 7, 2005, for example, and then something happens that completely changes you. I became interested in how some people seem to cope well while others get stuck with awful memories, become hypersensitive and fearful.”

He is looking for more interviewees, particularly recent war veterans, who can contact him via his website, www.johnmarzillier.com.

* The Gossamer Thread is published by Karnac Books at £12.99.