Many years ago I went to an isolated village in Switzerland to report on a renegade Freudian psychiatrist and analyst called Dr Silvio Fanti. Fanti, now deceased, had developed a controversial technique – micropsychoanalysis – that was highly criticised at the time, but in retrospect, makes a huge amount of sense. He believed, quite simply, that life was too short to spend in analysis. So he cut the time frame drastically.

Fanti would have two patients stay in his sprawling home for several months. There, they had analysis three hours a day, three days a week, rather than the traditional Woody Allen-style analysis of lying on the couch talking about one's mother for 40 years. He reported that nearly all of his patients emerged "cured" or at least relieved of their symptoms.

The Hoffman Process, which has become more and more popular in Britain in the past five years, takes the Fanti approach without the Freudian spin. It has been going since the 1960s but has grown drastically in the UK, especially since various celebrities have come out and said they did it.

The Hoffman uses various techniques, from Eastern mysticism to deep meditation, Gestalt, group therapy, visualisation, and allegedly condenses a lifetime of analysis to eight days. It has become, for many people, a life-changing experience that surgically removes their negative habits. Many who finish The Process, as it is known, become evangelical, as with Alcoholics Anonymous.

But proselytising, in fact, is not the intention of the American founder, Bob Hoffman, who started teaching in 1967 to help people lose their "negative love patterns". Negative love is all that bad stuff those two people ("They fuck you up, your mum and dad . . .") pass on to you, intentionally or unintentionally.

I found myself on a freezing train platform in Sussex very early one Friday morning with a clear personal goal: I never want to pass on to my six-year-old son all the dysfunctional stuff my own parents had generously passed on to me. Also, to address the unrecognised trauma of 20 years of reporting conflict, which occasionally manifests itself in my life in unexpected ways. I was sceptical, to say the least. I resist any "reaching out" and I am not good at "sharing" my problems.

But a writer friend, who had gone through The Process, kept prodding me. "It works, it just works," she said. Over lunch, she talked me through it – although like all Hoffman graduates, she could not tell me details of what goes on. I guess if you knew what was going to happen, you probably would not go. You sign a confidentiality agreement promising not to disclose others' private stories. The one thing she told me was: "Listen. Don't intellectualise everything. They will ask you to do stupid stuff. Your brain will say: I am not doing this. But just do it. There is a reason. And, remember, it works."

Another friend's 22-year-old daughter with "issues" had come out of it "totally and utterly changed". I did not need utter changing – but I did realise where my traumas lay, and thought it would be nice to shed them. Long fascinated by psychoanalysis, I also wanted to go as an anthropological exercise.

So off I went with my little backpack. I thought I was prepared, having spent hours filling out forms about my emotional and psychological life, my family history, my history of trauma. I thought I was prepared: I had "done" boot camps before – yoga boot camps, ashrams, detox (of toxins, not drugs) boot camps, even SAS military boot camps to prepare me for hostile environments.

But the thought of The Hoffman and all that sharing left me unnerved. AA regulars say there is nothing more powerful than a group to guide you through difficulties, to make you stronger. But I come from a long line of deniers. My mother's father died of alcoholism in his 40s and she has never once uttered the word alcoholic in connection with him. She says, "Darling, Daddy liked a drink or two." As for me, only my tiny band of intimate friends ever know what is really going on. The rest get: "Life is wonderful." It's just how I was brought up, like Scarlett O'Hara: lie about what you feel and what you think. It's not very feminine to do otherwise. Or, as a young Hoffman colleague said: "I lie to everyone. Even the taxi driver who brought me here."

Inside the house where I was to spend the next eight days, I met my 23 "comrades". We sized each other up. There were businessmen and women, poets, playwrights, writers, students, an actress, a mother of five. My roommate was a quiet, northern red-headed businesswoman, who looked as freaked out as I was. There were days when we were meant not to utter a word, but both of us burst out laughing and decided to bin that behind closed doors.

That first day, we sat in a circle where we would spend a lot of time that week. I looked around the room – here was a "buttoned-up public school boy"; there was an "attention-seeker"; and that woman in the corner was "a woman who does not like other women". This is part of the learning curve too: nothing was as it seemed. The readiness to judge is so linked with the negative patterns all of us had come to lose.

The women on either side of me both later admitted they loathed me on sight. One, whom I grew to love dearly, said: "I thought you had no sense of physically boundaries, you kept wiggling in your chair and knocking into me." The other – a fierce-looking poet who scowled but who ended up making me laugh and laugh – thought me aloof. "But I love you now," she said. Three seats down was another woman who, like me, did not utter a word more than she had to for the first 48 hours.

Later, I would realise that everything was intentional – where we sat, who our roommates and teachers were. Our teachers – we were each given one who would guide us through the week ahead – had carefully read our histories. So carefully, that when I was not "getting into it enough" during a Gestalt exercise, my teacher came over and whispered something so painful in my ear that I responded, uncharacteristically, like a maniac. Which is exactly what he wanted: to push my buttons, or to break me down, so to speak, in a controlled environment, and then to rebuild me. I think I actually saw him smile as I went nuclear.

We worked long hours – from 8am until 10pm. There was no time for reading, walking or DVDs. We were meant to hand over computers, magazines, sleeping pills and telephones. I lied and kept my BlackBerry and my sleeping pills. After three days, guilt took over and I went to Matthew, my teacher, and handed them over. And that was the end of my contact with the outside world.

Most of the work is in the form of powerful meditation. Visualisation plays a strong part in it; as does journal-writing and drawing, and, of course, the group sessions, which grew less painful but more challenging: admitting transference, it seems, is important.

The first four days were excruciating and exhausting. No getting around it. Then it got – while not exactly easier, because every day unearthed some new layer – lighter. The final days were spent on how to deal with the outside world. By that point, I wanted to get out.

It is advised that you spend the weekend after The Hoffman by yourself, listening to tapes and meditating. I knew that was not going to happen. I decided to stay with my best friends. So I got a ride with one of my comrades but when she dropped me off in London, I suddenly felt incredibly shaky. The noise was so much more potent; the people shoving and pushing on the pavements more menacing. I wished I had listened to their advice and stayed holed up in a B&B in Sussex.

Months on, can I say my life is drastically different? No. Partially it is my fault. I would like to say I followed the instructions and did my meditations; checked in with my emotional, physical and spiritual self every day; and stayed in touch with my comrades. I tried, but found it another techno burden, like checking Facebook, BlackBerry and email. I don't meditate as much as I would like to. I did not go to follow-up meetings.

But I did maintain something that is hard to describe. Peacefulness, more awareness, and, very specifically, the very thing I had come to lose, I did. It was – as my teacher Matthew told me – surgically removed. Or more to the point, spiritually removed.

And, stranger still, on the train back home to Paris, I thought of that trip 20 years ago to Dr Fanti's mountain village. I was a young girl at the time, and not very self-aware. The analyst had grown attached to me and, at the end of my stay, we spoke for a long time. Even though I was not a patient, he had whispered some advice to me about the life that lay ahead of me: "Until you address this about yourself," he had said, about a certain "issue" of mine, "you will never find true peace." When I got home, he had sent me three dozen roses for my birthday with the message written out again in his careful script.

On the train home, I realised I had at last got over the issue Dr Fanti had talked about all those years ago. So, as strange as The Hoffman is – as the devotees say, whatever works.