My stage act worked a bit like karaoke, but instead of using alcohol to lower people's inhibitions, I used relaxation, suggestion and positive reinforcement. It then feels like the most natural thing in the world to stand in the spotlight and act like Mick Jagger. A guy called Christopher Gates came on stage at High Wycombe one night in 1994. He did some silly things, we had a few laughs and he was the star of the show. A few days later his girlfriend contacted me to say he was behaving weirdly. He was then admitted to hospital and diagnosed with schizophrenia.

Hypnotism has always had a bad press, so people were ready to believe there was some kind of mind-bending involved. I could see a storm gathering from the psychological community. Psychiatrists don't like me. Why would they? You spend your life learning to be a doctor and cure people of phobias, then I come along and do what they do - better and in less time.

As soon as the story broke I stopped touring; adverts and corporate work were cancelled. I worked out the case cost me four or five million quid. But the money was the least of it. I was so traumatised I couldn't sleep, I lost a lot of weight and I began to believe my own bad publicity: I could help other people with stress control, but I couldn't help myself.

I remember the first day of the trial vividly. If it hadn't been so tragic, it would have been funny. The first day, Chris Gates's QC, Anthony Scrivener, stood up and said solemnly: "Before becoming a hypnotist, m'lud, Mr McKenna was a disc jockey," as if that put me in the same bracket as a serial killer. A psychiatrist claimed I had "cast a spell on Mr Gates". I was in a 20th-century courtroom being tried for witchcraft. But instead of being ducked in the lake, I'd be bankrupted and shamed. An eminent professor came up with research suggesting I'd caused Chris Gates's schizophrenia without ever having met either of us. He was mangled in the witness box - that was a beautiful moment. Then a rival hypnotist gave evidence against me. My QC made such a c*** of him in the box, it was fantastic.

At the last moment a load of big guns from the medical industry came to my rescue. I think they were appalled at the ignorance surrounding schizophrenia, which is a biological condition, a genetic predisposition. You can't catch it, nor can hypnotism cause it. The prosecution then claimed that going on stage brought the condition on sooner. My QC pointed out that Chris Gates had been in a hit-and-run accident and he'd lost his job. But apparently none of that was as stressful as coming on my show and dancing like a ballerina.

I was cross-examined over three days, which was hard, but I think of myself as a very skilled communicator. I knew all the tricks and I wasn't going to get tripped up. Did I hypnotise the judge? Of course not. But I did use psychological techniques to put my case powerfully.

The day of the verdict was a bun fight. The judge said I was not negligent and could not be criticised. My hands were shaking as I read out my statement in front of a sea of photographers. I was thin, I was pale. I think the whole thing aged me. Had I lost, I could have been sued by every opportunist in the country. My biggest fear was that I'd win but my career would be ruined. Thankfully, that didn't happen. The irony is that all I'm able to achieve now as a therapist and a motivational writer is only possible because of the shows I did for so many years. I showed people that hypnotism is powerful and it works. Getting a grown man to think a broom is a supermodel and snog it isn't so far from getting him to believe he can stop smoking. In the last year, I've cured a case of hysterical blindness and successfully treated a group of infertile women. Nowadays the psychological technology exists to wipe out phobias in an hour and cure people of addictions and compulsions.

I can cure most people of most things. Going to that place where you think it's all over gave me a new sense of value.

I looked over the edge of the abyss and glimpsed having nothing. That filled me with sadness because I have great plans for my life. I signed up for the rich-and-famous bit, not the evil-mind-bender bit, and it makes me angry to think it could all have been taken away, just like that.

Instant Confidence, by Paul McKenna, is published on January 16