On Athletics:It always interests me to know the different ways people like to write. Among the more unusual discoveries of late is that Bob Dylan likes to write while moving - one of the many insights he reveals in his autobiography, Chronicles.

"You can write a song anywhere, in a railroad compartment, on a boat, on horseback - it helps to be moving. Sometimes people who have the greatest talent for writing songs never write any because they are not moving."

Writing while static is more common, though still varied. Truman Capote regarded himself as a completely horizontal writer: "I can't think unless I'm lying down, either in bed or stretched out on a coach and with a cigarette and coffee handy. I've got to be puffing and sipping."

Ernest Hemingway was a completely vertical writer. As George Plimpton found out when interviewing him in 1958, Hemingway liked to write standing up: "He stands in a pair of his oversized loafers on the worn skin of a lesser kudu - the typewriter and the reading board chest-high opposite him."

Dylan's approach works well for me, as I usually write best while running. Not strictly speaking, as that would look rather foolish, but after a long run in the hills I often have a full article worked out in my head, then quickly sit down to write it. What you're reading now was effectively written while I ran the roads around the Blue Light pub in the Dublin hills.

Running, I've gradually realised, goes way beyond putting one foot in front of the other as quickly as possible. It wasn't always this way, and for years I couldn't understand why people would want to run unless it meant hammering a 10-miler on the roads, or breaking 30 minutes for 10 kilometres. The casual or recreational runner, who ran for health, fitness, and general well-being, was to me a lost cause. Sorry, but get out of my way.

This view has now changed.

A group of friends have just signed up to run the Connemara half-marathon in April, and although they have no athletics background, and never ran to exhaustion in their lives, they've become almost obsessed about their training. Running, it seems, has given them a new purpose to their daily lives, and they swear they're better for it. I've just signed up to run too.

The physical benefits of running are well accepted, from strengthening the heart, to putting a monkey wrench to body fat. Yet the mental benefits are only now being widely recognised. Most people have heard of the "runner's high", but this was a little too vague for the medical profession, who preferred drugs, or something more drastic, when it came to treating so-called mind-related illness.

According to the British Mental Health Foundation, one of five GPs now prescribes exercise, as an alternative to drugs, in treating depression. This represents a fourfold rise in three years. And it works. Whatever about being born to run, it seems there is more to be gained from life with the simple act of running.

Just ask Ronnie O'Sullivan, the two-time world snooker champion who has just regained his number-one ranking after a long struggle with depression. Two years ago, O'Sullivan walked out on the UK championship quarter-final against Stephen Hendry, suffering from what he said was a severe mood swing.

Earlier this week, in a fascinating interview with BBC Radio 5 Live, O'Sullivan put his recent return to good form, and good mental health, down to one thing: running. Believe it or not, he now rates his running as more important than his snooker, and part of his preparation for this week's Welsh Open was to run last week's Essex cross-country championship, where he finished 28th.

O'Sullivan now runs around 50 miles a week, and while initially taking it up to lose weight, he has realised the advantages go way beyond that: "I used to wake up in the morning and brush my teeth. Now it's wake up in the morning, brush my teeth, and go for a run.

"I've tried many, many things to combat my demons, and this is the one that just does it for me. Plus I enjoy it. I feel unbelievable, so strong and fit in myself. It makes me put life much more into perspective, because I feel good in myself. I used to drink a lot, and do all that kind of stuff . . .

"But I was never satisfied. Since the age of 20 I kind of hit a downward spiral, for like four or five years. I got myself into the Priory, and ever since then I've been trying to sort myself out really.

"I used to get down on myself a lot, was real hard on myself, and if I didn't achieve would go into dark depression, shut the world out."

Still only 32, and still regarded as the most naturally talented snooker player of all time, O'Sullivan now considers himself a runner first: "If I had a choice between my exercise and snooker, snooker would go. It comes well behind the running. The running makes me feel great in myself. I would encourage my family and kids to do it. It's just where it's at for me. Once I do that anything is possible. Without it

. . . I can't even go back into that black hole."

After listening to O'Sullivan, I thought of the sprinter Dwain Chambers, and why he still likes to run. Ostracised by fellow athletes, banned from the Olympics for life, and now rejected by meeting promoters all over Europe, Chambers is paying the price all drug cheats should. But if he still wants to run to keep his head straight, that at least is understandable.