In his latest book, journalist, novelist and columnist Jon Ronson delves into the 'madness industry', but after becoming a professional psychopath-spotter it was he who needed help, he tells SHANE HEGARTY

AS A film-maker and author Jon Ronson has ventured into various shadowy corners: the obsessions of Stanley Kubrick's Boxes, the extremists in Them,the bizarre psychedelic experiments of the post-Vietnam US Army for his book The Men Who Stare At Goats– later turned into a film starring George Clooney and Ewan McGregor as a version of Ronson.

Imbued with his typical humour and self-examination, his latest book, The Psychopath Testtakes a checklist developed by psychologist Robert Hare as a starting point to look at the theory that psychopaths gravitate towards high positions in business and society. However, it becomes an examination of the "madness industry", journalism and the over-diagnosing of psychiatric illness, especially with children.

The Irish Times : Since you found yourself portrayed on the big screen by a movie star, how does it change your own sense of self? Did you find yourself as you were writing this book wondering "Who will play me in the next movie?"

Jon Ronson: The funny thing about the whole Men Who Stare at Goatsfilm thing is that one day when the film's being premiered, you're on the red carpet, and people are snapping your photograph and you've got a limousine on standby and you're meeting George Clooney, and he comes in the room and goes "Jonny!" and all of that. And the next day – nothing. It's all gone and you're completely back to normal. And I've been completely back to normal ever since . . . and when I was writing The Psychopath TestI realised everything is hard enough without thinking about possibilities of movie adaptations, so I realised very early on that if I started having half an eye to the movies with this book, I would just write a terrible book.

IT: The book is a real mix of The Men Who Stare at Goatsand the journalism and column you were writing for the Guardian

JR:Yeah, that was quite deliberate. I used to write this column in the Guardianabout small domestic anxieties. And you know I was never really happy doing it. I had high intentions for it which I think were never realised . . . I had this idea that with Themand The Men Who Stare at Goats, I was writing about bubbles of madness that were happening a long way away from us. The Men Who Stare At Goatswas a very particular sort of niche – US soldiers in bases a long way away from our lives – and I thought the madness that's really important is our own domestic madness, the thing that drives us to get into completely stupid fights with our neighbours or become inadvertently bad parents. However when you do write about it in the form of a weekly column in the Guardian, you kind of turn into Liz Jones, you turn into one of those annoying people, which was never my intention for it. So when it came to me writing The Psychopath Test, I made the conscious decision that I wanted to mix those two things.

IT: What exactly is the book about?

JR: It essentially begins with a theory that is shared by psychiatrists and psychologists and eminent people around the world which is that psychopaths rule the world. This brain anomaly that leads some people to become killers, leads other people to become ruthless, vicious CEOs and in fact, capitalism is a physical manifestation of psychopathy.

It sounds like a conspiracy theory, but it wasn’t conspiracists who were saying this; it was Harvard academics. This struck me as such an enormous thought that I wondered: is there some way of proving it or disproving it?

And what I discovered was that you could go on a course that teaches you how to become a professional psychopath-spotter. So I did the course, and became a professional and then journeyed into the corridors of power to try and see if this theory is true.

IT: Without giving too much away, because there is a mystery to it – you use the word sleuthing quite a lot – it's about your certainties getting gradually eroded as you go along.

JR: One of the main real shocks was after becoming a psychopath-spotter, I started spotting psychopaths everywhere, and I turned into a sort of hard, callous person, trying to shove everybody into a madness box which really shocked me, I mean I really got trapped inside that bubble.

And when I realised what I’d become, then it becomes a book about morality and how easy it is to become the person who presses the button in the Milgram experiment [in which people were encouraged to harm others]. And then it becomes a book about journalism and how we’re all scouring the world looking for suitably mad people to exploit for the entertainment of the people.

IT: The checklist itself was put together by a guy called Robert Hare . . .

JR: Yeah, a Canadian. For all the ambiguities and shifting sands in this book, there are certain truths, and one of them is that when people's brains go wrong, they go wrong in uncannily similar ways and so psychopathy does exist. There is a line in the sand where somebody has no empathy and you really can spot them by studying the nuances of their behaviour, like their sentence construction and so on, which so like amateur sleuth territory. And he's developed this checklist, a 20-point checklist and basically if you score 15 out of the 20, you're a psychopath and that's it. And if you're in the wrong place at the wrong time, for instance in court for GBH, and they deem you a psychopath, there are certain parts of the world where you'll be locked up and have the key thrown away.

IT:You talked about how much you were seeing psychopaths everywhere. Do you still find yourself looking for them?

JR: I think I've reached a better place now. When I do come across one who really is one, I know. And it is a kind of interestingly arcane knowledge that you have but I don't think I'm rife with confirmation bias and spotting them everywhere any more, which I was doing for a long time. Although, it is a terribly seductive and unpleasant thing, but nowadays when I pick up the paper and see Mladic's arrest and see him in his grandiose outfit, and then you hear about Dominique Strauss-Kahn leaping out, if he did do it, and so on, instantly you go into psychopath-spotting mode – which is good and bad.

IT: When you talk about journalism in the book, has it challenged your own ideas of what you want to do as a journalist and what you want to work on next?

JR: It has, and I haven’t come to a conclusion yet. I tell you what the problem is, when you don’t do it all, when you’re deliberately writing about people’s ordinariness rather than their madness, people don’t like it. The readers don’t like it, the editors don’t like it. I’m thinking specifically about this documentary that I made for Channel 4 that really didn’t do well. It’s about the Alpha course – agnostics taught how to become Christians – and I was so conscious of not portraying anyone in the film as being at all kind of nutty that kind of nobody liked the film. So you’re in a difficult position where you don’t want to be immoral but you want people to like what you’re doing. It’s tough. You have to try and find a way through it and do was well as you can.

The Psychopath Test

by Jon Ronson, Picador, €16.99