We hear the subject of self-harm mentioned in the media rather a lot these days. It's a mysterious phenomenon that appears to be on the rise.

In fact, it's the third largest cause of death among 10-13-year-olds in the UK. It's also on the increase in men in the 20-35 age group. You might think that the last thing someone suffering from extreme anxiety or depression would want to do is cut their arms with a razor blade. And I'll admit I also struggled to understand why the young and the not-so-young would deliberately hurt themselves.

Or I did struggle to understand, until I broke a toe a couple of years ago. I'd been worrying for weeks about a possible book tour, involving several days' worth of my twin phobias, flying and public speaking. I hadn't slept properly and I was even losing weight through the worry of making a fool of myself and ending up on YouTube; fainting on live TV, for example. My publishers in several countries were waiting for an answer and I was trapped in a cycle of worry from which there seemed no escape. If I went, I could feel terrible. If I didn't go, how would the readers ever get to know me?

And then I came running in from the garden to answer the phone, tripped over the doormat and suddenly my foot seemed to be on fire with pain. It took me a few seconds to realise that I'd caught a toe under the doormat and broken it. It was my first experience of broken bones and the pain was out of all proportion to the size of my puny little toe. I was literally speechless with the agony of it. I was whisked off to A&E by my devoted husband, where all I got for a one-hour wait was a plaster, to strap my broken toe onto the one beside it.

The thing is, as I took a couple of painkillers later that day and sank onto my bed to watch Diagnosis Murder, I realised I'd temporarily forgotten about my dreaded book tour. And the self-harm question began to make sense. Physical pain is occasionally so overwhelming that it blocks out anxiety, depression and even obsessive thoughts. Is this why so many people are deliberately hurting themselves, I wondered?

It's a tough world out there. Women are torn between motherhood and career. Men are struggling to live up to the achievements of their increasingly macho role models. Working class men have never found it more difficult to find and keep well-paid work. The soaring cost of living means that only those couples that are both high earners can have a comfortable lifestyle these days. Although it has to be said that a high salary inevitably brings with it a lot of responsibility and stress.

Children whose parents are still happily married to each other are sadly in a minority as divorce rates spiral above 50%. We're bombarded with envy-inspiring images of beautiful celebrities and their fabulous homes and possessions, and also with disturbing images of war and famine. It's no wonder we're all living in the shadow of the stress monster nowadays.

In the end, I said no to the book tour. It would have been too difficult for me. After all, I'm the sort of person who is so hopeless at public speaking, I would refuse to even read out a short prayer at a family funeral. Instead, I offered to write several short stories for newspapers and magazines, and to part-finance some promotional gifts. I simply decided to stop worrying and take positive action. Admittedly, I hadn't reached the self-harm stage, but I think I did get a small insight that day into what causes some people to self-harm.

The mental health charity Mind tells us that some people self-harm because they've had damaged childhoods. Others use it as a coping mechanism. There's no social or class barrier. Amy Winehouse is infamous for her scarred arms, despite being hailed as the most talented songwriter in the world today. The late Princess Diana also talked about how she self-harmed, as has Olympic champion Kelly Holmes. But it's not easy to admit to self-harming, and even when sufferers do come forward, there are precious-few facilities to help with diagnosis, counselling and treatment.

My advice as a lay person, to any self-harmers in our society, is to actively seek out practical ways of dealing with the issues that are causing you stress. Be it leaving a difficult relationship, seeking practical advice on tackling mounting debts, seeking treatment for an addiction problem or setting more realistic life goals for yourself. I would also recommend a visit to a sympathetic GP who may be able to arrange for some counselling sessions. Obviously, remaining in denial about the problem will not make it go away.

I would also ask family members of sufferers to be sympathetic and understanding and accepting of this very difficult health issue. The last thing that anybody needs when they're at a low ebb in their lives, is a pull-yourself-together lecture. Perhaps a kind word and a simple hug from a loved one could be the first step on the long road to recovery?

Me? I'm still trying to build up enough courage to go on that book tour. I know it's not a life-or-death issue. And that my coping mechanism (avoidance) isn't likely to land me back in A&E any time soon. On a positive note, I suppose that owning up to my own weaknesses has made me a much more sympathetic person than I used to be.

So I'll end with a note of support to any self-harm sufferers reading this column. You are good and gentle people: otherwise you would not feel emotional pain so acutely. Please seek help. You are a worthwhile human being and you deserve to be living a better life.