Positive thinking makes me sick: JENNI MURRAY on why she hates the self-help industry

Someone I'd thought of as a good friend first encouraged me to embrace what she described as 'The Power of Positive Thinking'. I'd just told her about what I saw as really rather bad news. I had breast cancer.

Her rebuttal of my justification for feeling a bit down in the mouth about it - I would have to undergo surgery and then either radio- or chemotherapy to control or maybe even cure a disease which is generally feared as a killer - was swift and uncompromising. I must not, she told me, have such negative thoughts. It was probably pessimistic thinking which had caused it in the first place. I must now be positive and heal myself.

I dismissed what she was saying as nonsense. No one knows what causes so many of us - around 44,000 a year in the UK alone - to develop this disease, but there were a few strong hints coming out of scientific research.

Top of the list for women like me who'd passed the menopause is an excess of the hormone oestrogen and I had been taking HRT for a few years so I was awash with the stuff. What I must do, she advised, was feel happy - she had read that happiness can cut breast cancer risk by a quarter. I must eliminate all negativity in relationships from my life, stop watching depressing news on TV and begin a programme of 'visualisation' and imagine the white cells in my immune system fighting off all the nasty cancer cells.