Vital signs: the difference between stress and a true breakdown

The pressures of fame can be intense and have claimed many victims over the years — Britney Spears being the most memorable with her head-shaving and wig-wearing episodes. Then there was Kerry Katona and that appearance on GMTV. Yet it's not just the unfortunate few who cower in the glare of the media who suffer. It is estimated that one in four of us will suffer from mental health problems at some point in our lives.

They can strike suddenly, the result of pressure that has slowly been building up and can leave us feeling totally unable to cope. Not just a bit flat, but totally incapacitated.

For most people it is not so serious, it's more about feeling low or being highly stressed, perhaps after losing a job, a partner — or a talent show competition. The most common responses tend to be to drink more than usual, lose your appetite for a few days and find it hard to stop crying.

But this sort of behaviour does not mean that we are clinically depressed or having a nervous breakdown. A true breakdown can result in total loss of control over one's life, paranoia, hallucinations, erratic behaviour and interactions.

Talking about your problems is the best way to alert yourself to your state of mind. I hope Susan Boyle has had suitable support throughout her ordeal and that she is simply resting. Actually I wouldn't be surprised if one or two MPs were found checking into the Priory with her. I wonder if those costs can be claimed back, too?

Just a small amount of sunlight produces a lot of vitamin D. The vitamin is made when a cholesterol-like molecule in your skin interacts with ultraviolet light. A lack of vitamin D can lead to bony deformities like rickets, common in post-war Britain and now occasionally seen in women who keep their skin continually covered for religious reasons.

But interesting results have been seen in population studies. It seems the risk of developing colon cancer is lower in people who live in sunny climates and follow-up studies indicate the vitamin is responsible for the protective effect of sunlight exposure on the incidence of breast and prostate cancers, too. But there is a down side.

Too much vitamin D can spill calcium into the blood and lead to heart disease and death. And we know that sunlight is the leading cause of skin cancer.

So how can you get the benefits of vitamin D without frying and prematurely ageing your skin and increasing your risk of getting skin cancer?

One answer would be to develop sunscreens that don't screen out too much UVB radiation, which promotes vitamin D production, but which do screen out UVA, which can trigger melanoma. There is another alternative, however: vitamin D is found in many foods like cod-liver oil and milk, and increasing consumption of these may give us the same benefits.