It is more than 30 years since the incident that changed Gary Williams's life, but it has cast a long shadow. While on patrol in Northern Ireland with the British Army, Williams's unit was confronted in a remote area of County Armagh by a group of armed republicans, and a gun battle broke out.

Williams's patrol partner, who was also his best friend, was advancing towards the men while Williams was supposed to be offering covering fire. His gun jammed and he couldn't clear it in time; his friend took a direct hit and died instantly.

The shoot-out, in 1976, lasted no more than 10 seconds but it was to torment Williams for decades. As well as living with other horrifying images from two tours in Northern Ireland, Williams was inconsolable over the death of his friend, Peter, and blamed himself for what had happened. For 30 years he struggled with regular bouts of depression, for which there seemed to be no lasting cure, until he was diagnosed six months ago with post-traumatic stress disorder (PTSD).

Williams admits the reason it took so long for the diagnosis was because he had pushed the details of the shoot-out to the back of his mind. He refused to talk about it to anyone for 30 years, unaware of its psychological importance, which makes it even more remarkable that, having just completed a pioneering treatment for PTSD at NHS Forth Valley, Williams is now free of most of its symptoms and says he feels as if he has been given his life back.

Williams joined the RAF in the early 1970s and was in Northern Ireland seconded to an Army unit, co-ordinating ground-to-air communications. He had already experienced other violent incidents, and taken part in clear-up operations after several fatal vehicle bombings.

"I'd just turned 18 and hadn't seen anything like that in my life, the maiming and mutilation. It horrified me," says Williams, 50, from Stirlingshire. He says there was little support from the armed services in dealing with traumatic incidents. "You dealt with things in your own way, often by going out and getting blind drunk," he says. After the shooting of his friend, however, Williams spent three months in the RAF's neuro-psychiatric unit, which offered some relief but never got to the root of the problem.

Williams left the RAF after 12 years and, like most veterans, had to deal with his health problems himself, through the NHS. It was the start of three decades of recurring depression and seeing numerous therapists, most of whose treatments were unsucessful. Even though he completed a degree at York University, and worked briefly in IT training, he says his problems became insurmountable.

"Doctors were treating me for depression, and that's what I thought I had. The incident with my friend Peter never came up. I never brought it up. I never spoke about it to anyone in all those years. I didn't understand that the depression was a symptom of PTSD," he says. "In the past, not much was known about PTSD, but after the Falklands, and the Gulf War, it was starting to be recognised," he says.

Late last year, Williams started having horrific nightmares and flashbacks of his time in Northern Ireland, and told his current therapist, who recognised his condition as PTSD and referred him for specialist treatment. Williams was sent to Therese McGoldrick, a behavioural psychotherapist at NHS Forth Valley, who had been having outstanding success treating difficult cases of PTSD, particularly using newer therapies.

She decided to give Williams four sessions of a ground-breaking treatment called the emotional freedom technique (EFT) which is an "energy therapy" available only through a few health boards, of which one is Forth Valley.

The board offers EFT along with a more mainstream treatment called EMDR (eye movement desensitisation and reprocessing), which McGoldrick pioneered at Forth Valley in the mid-1990s. Her research into EMDR won her and her colleagues international recognition and has opened the way for the use of newer therapies such as EFT. They are about to conduct a trial, the first of its kind in the world, on EFT.

EFT is based on an idea that energy flows around the body along 14 meridian lines, which can become blocked by negative emotions. During EFT, the therapist taps these points on the face, body and hands with the fingertips while focusing on emotions surrounding the original trauma.

McGoldrick has worked for more than 20 years with trauma sufferers from disasters such as the Lockerbie bombing, the Dunblane massacre and the Piper Alpha explosion, and has treated veterans from a number of combat zones, as well as victims of serious crimes. She soon found that conventional "talking therapies", while useful for many conditions, did not help with trauma. While it's a controversial point, McGoldrick believes these therapies don't really work, because trauma involves part of the brain not accessible through language. McGoldrick says traumatic experiences are stored in the part of the brain that controls emotions, where they can become trapped and are not processed. Instead of becoming filed as a memory, they persist as if they have just happened.

"When you ask a person to talk about the trauma, the fear centre of the brain tends to fire up again as they relive the trauma situation," says McGoldrick. The tapping procedures of EFT help to release the experience from the emotional part of the brain, she believes.

After his four sessions of EFT with McGoldrick, Williams says: "I'm gobsmacked at the speed and effectiveness of the treatment. You feel the benefits within minutes of going through the tapping routines. With EFT I was able to talk about the shooting incident for the first time. With each session, my memory of the incident became more acceptable, and my emotions less negative. I do have the images of the past, but they cause me no pain now. I totally accept the shoot-out incident now and that I had no control over it, it wasn't my fault. I don't blame myself anymore."

McGoldrick says that both the new techniques are proving invaluable with significant traumas associated with war, rape or serious accidents, but they are also useful in treating "small" traumas. "Recent research has indicated that a number of normal' life events such as redundancy or bereavement can give rise to profound symptoms of PTSD," she says. This could see them being used to treat a wide range of psychological disorders.

McGoldrick says EFT may offer hope to veterans returning from Iraq. Williams adds: "I'm sure veterans will be going through some of what I experienced, but I hope and pray they will receive proper treatment and won't suffer for as long as I did."

EMDR Institute website
Emotional Freedom Techniques website