What happens after the killing stops?

"Within a series of hostile environments over a number of years, I was... witness to and involved with a series of events that led to a situation where I couldn't live with myself any more. So the nightmares and flashbacks began," Bob Paxman, a former SAS corporal, says of his descent into the hell of acute, severe and complex post-traumatic stress disorder (PTSD).

"I was savagely aggressive. Everything became out of context, and when I left, it got even more out of context. I became a security consultant in Iraq and Iraq became my home. When I came back to England for a two-week holiday, I'd go to places like Tesco and I'd want to start filling people in. I'd drag taxi drivers out of cars because they said the wrong word to me. I was on edge the whole time. When I was out there, I'd volunteer for all the dirty jobs, the ones no one else wanted to do because the chances are you were going to get caught or possibly killed, and possibly I was looking for that. I was very good at those jobs as well."

Paxman now spends his time promoting a therapy for post-traumatic stress disorder that he has developed with another one-time squaddie and plain-clothes police officer, Ernie Dowell. Dowell has a ready supply of similar stories, describing himself as former medically prescribed "smack-head" who tossed back 30 or 40 different pills every day, in a largely unsuccessful attempt to cope with a life gone off the rails. It was only when his doctor told him he ought to be dead that he was brought up short, went cold turkey and started trying to find a way to beat up his demons rather than himself.

It's a slightly surreal experience hearing these two men relate these stories. They don't show any outward signs of personality dysfunction. While that's not necessarily unusual for people with psychiatric conditions, I spend two days around them, including having dinner with Paxman and his girlfriend before repairing to their Liverpool flat. He comes across as a relaxed and well-adjusted individual.

What's more, neither he nor Dowell give off the aura of the "tough guy", cultivated, perhaps subconsciously, by some current and former military personnel, policemen and athletes who play contact sports at a high level. And Paxman is a fairly imposing physical specimen, as one might expect given his background. "We're all works in progress but I've got past that," he says. "Now what I want to do is help people."

How he does this is with Talking 2 Minds, a charity he founded with Dowell that offers courses aimed at dealing with the symptoms of PTSD. Largely to ex-forces personnel, although they have also taken on some of Liverpool's high number of drug addicts and the victims of other traumas. They include traffic accidents, which is where I come in. I'm here, if you'll excuse the pun, to road test their "Paradigm" therapy. Two-and-a-half years ago, I was run over by an oil tanker while riding my bike.

While Paxman admits his malady manifested itself in aggression, that's not necessarily typical for people suffering from PTSD. My wife describes my symptoms when presented with a stressful situation thus: "It is like you are not there, that you are physically there, but mentally you are not. If I speak to you I don't get a response. You stare ahead, into nothing. It's almost like you are trying to protect yourself."

Not long after the road accident that brought me as close to death as it is possible to come, I had a number of therapy sessions, which did help. But the anxiety attacks, sleeplessness and struggles dealing with stressful situations persist and have recently become more bothersome. Much of the treatment I received in the first instance involved my therapist attempting to desensitise the bad memories. Paxman believes in a different approach: "All trauma-focused therapies are doing is re-traumatising the guys. Can you remember, what did it smell like, what did you see? And they're right back in it. They get you to relive the trauma and try to desensitise it. That, to us, is abominable, that you should go back and make someone relive that trauma. It's too intense and each time they remember it they add to it.

"What we're looking at is the negative emotions that are attached to that event. And we're not dealing with them there. Let's say fear is involved. Through a scripted process we are following that emotion back to the childhood amnesia phase, where it was first created metaphorically in the unconscious mind. Then we assist the client with neutralising that emotion, and stripping it out through all of the events that are traumatic, drawing the poison out. So you still have the memory, but with no negative attachment to it."

He says their treatment is aimed at those for whom other methods have failed: those whose conditions are "severe, complex and acute". I don't think I'm in quite that deep a hole. But symptoms such as insomnia and anxiety are deeply unpleasant and I'm willing to try anything that might help me deal with them.

I sit down opposite Dowell in a spartan room on the first floor of their Liverpool base. He puts on some music – one of Peter Gabriel's recent experimental outings, which wouldn't have been on my playlist but rapidly fades into the background – and we talk. He asks me to go back to my earliest memory of fear, which in my case goes back to the confused, half-formed memories of being diagnosed as a type 1 diabetic at the age of two. We work on visualising the feelings associated with those memories, and on combating them. We discuss my chronic insomnia and the anxiety, often at night, that attacks like a quiver full of arrows tipped with paralysing poison. I visualise the feelings as a sort of grey monster, an amorphous, malevolent blob.

"Have you ever had a conversation with it?" Dowell asks. "Asked what it wants?" That is daunting. So did he? "Yes," he says. "It wanted to hurt me. So I told it that it wasn't going to hurt me any more. And that it could go away."

I try it. And the strangeness of the situation strikes me. I'm sitting in a room, visualising a horrible creature flipping me off. I respond in kind, raising imaginary fingers into a two-fingered salute. After a brief stand-off, it hustles away. I've used the technique since then and have found it effective. There are others, which are more familiar to me as relaxation exercises; he gets me to lean back and allow a moderate feeling of euphoria to wash over me. Dowell then suggests I squeeze my index finger and thumb together to turn this feeling on, to calm feelings of anxiety. By the time we have finished I'm ready for coffee. To my surprise, we have spent more than three hours doing this. What is helpful is that the person I am speaking to has experienced similar symptoms to those that assail me, something most therapists haven't.

As for results, an academic paper has been drafted by Dennis Carlon, a member of a four-strong "ethics committee" that oversees the work. It suggests that this is a programme that may be worth wider exposure. I found the subsequent drive back home, down an M62 and an M6 choked with traffic, remarkably stress free. When I arrived home my wife told me I appeared unusually relaxed. They have offered me the chance to do a full course and I think it could be worthwhile. Paxman says: "We find some people can do it [learn to deal with their negative emotion] immediately, some it takes several sessions. But we find with about 80 per cent of the people who come to us it takes between two to four days for them to say, 'well I've got no emotional attachment memory any more so that it's not a drama'."

He says mental illness is common among former comrades; some of those who have been helped had been living in forests or caves, too frightened to reintegrate into a society they could no longer cope with. Accurate figures are thin on the ground and are complicated by under-reporting: the British stiff upper lip has a lot to answer for. When I ask Paxman for his estimate of incidence among his former comrades, he puts it at as high as "90 per cent", arguing that one would have to question the mental state of those who would voluntarily put themselves through what he has been through. Dowell points out that people in the forces are taught to be violent, albeit in a controlled environment, and even to kill. "The problem is, they get out and nobody teaches them how to switch that off," he says.

The courses are free to veterans, but this is not a wealthy military charity. It is operated from a modest office in Liverpool, which is provided by the local council for a peppercorn rent. What money there is largely comes from volunteers doing stunts, wing-walks, parachute jumps, sponsored expeditions and the like.

Self-help treatment for psychological conditions has become a multimillion-pound industry that has made a lot of money for a lot of people, partly because what is offered on the NHS is inadequate. Accessing what is available is next to impossible, as I can attest having been metaphorically flipped off by a receptionist at the place I was referred to. Talking 2 Minds is modest, and what it offers is cheap and, apparently, effective. They're worth talking to.

talking2minds.co.uk