CATASTROPHE IN THE MAKING I am irresistibly drawn to nutters. The highlight of the week, for example, was bumping into David Icke at Heathrow. Icke is always a delight. I do not, like him, believe the world is ruled by a secret group of reptilian humanoids, whose members include the Queen. And yet it is when I am with people who do that I feel most alive.

This is probably because I am a catastrophist. The difference is that my catastrophism manifests itself in domestic paranoia rather than conspiracy theories. It last struck on Wednesday, when I flew to Scandinavia to appear on a talk show. When I called home and my wife didn’t answer by the third ring, I developed an image of her dead in bed, having accidentally suffocated under a pillow, and of our 11-year-old son pulling on the flex of the just-boiled kettle.

CLOONEY AND SPACEY I live in a permanent state of anxiety. That is why the fringe of society appeals to me, and why most of my writing and television work has been about extremists. But the fringe is loosely defined. I recently joined an Alpha course for a documentary I was making for Channel 4. Many of the recruits arrived on the course as atheists, but by the “away weekend” they were talking in tongues. Arguably, that is just as irrational as believing reptiles rule the world.

It is always a relief to have a mundane problem to distract me — such as how to get to the premiere of the film adaptation of my book The Men Who Stare at Goats. The cast includes George Clooney, Kevin Spacey and Ewan McGregor, but my wife and I haven’t quite got into the Hollywood mode. We decided a limo would be extravagant so we drove, and spent half an hour trying to park. I enjoyed waving at the fans. But they had come to see the stars, not me. There is something oddly sobering about walking up a red carpet and realising that of the thousands of people, not one is screaming for you.

CLOSE ENCOUNTERS The book is about the new-age influence on the American military, and — astonishingly — the story is true. In 1979 a secret unit was established within the US army to train soldiers in psychic kills. They would be taught how to make themselves invisible, and kill goats by staring at them.

Celebrities are particularly susceptible to craziness. I once went with Robbie Williams to meet alien abductees in Nevada. It became clear Williams felt a great sympathy with them. In a sense, he and the abductees had followed a similar path. When he was a 16-year-old he had suddenly joined Take That and become famous. That must have felt just as weird as going up in a spaceship. When I am researching eccentrics, I immerse myself. I slip into their world of paranoia. But by the time I sit down to write, I’ve come out on the other side. Otherwise my books would be unreadable — and I would be impossible to live with.

BEAUTIFUL GARGOYLE When not travelling, I live in Hampstead, north London. For the most part, my life is simple. It consists of three things — researching, writing and being a father. Other than that, I just run. I have become fanatical about it. I was recently in Disney World, Florida, and there were people so fat they had to be pushed in wheelchairs. It was horrifying. I am a slim, beautiful man and I’m determined to stay that way.

I had always thought my domestic habits were clean. But the other day I was in a restaurant, and a teenage girl at the next table was larking about, mimicking someone eating like a gargoyle. I was watching her while I was tucking into my soup — and suddenly realised to my horror that she was mimicking me.

TOO CLOSE TO HOME I grew up in Cardiff, and hated it. Wales was a ghastly place. The most inspiring thing that happened to me as a child was seeing a double bill of Woody Allen’s Zelig and Martin Scorsese’s The King of Comedy, and realising there was a better world beyond Cardiff. I escaped as soon as I could.

I used to write about my family in a newspaper column, but a while ago I had a sense of foreboding and suddenly stopped. When the furore with the novelist Julie Myerson and her son broke out I felt vindicated. I would have hated us to have ended up like that. I have vowed I will never write about my family again.

I was once asked if there was a danger I might end up as a crazed egomaniac, such as the people I write about. But I don’t think so. You need a lot of energy to be an extremist — and I’m too tired.

The Men Who Stare at Goats will be released on November 6

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