IT seems to be a simple enough question: Should one try to be happy or miserable?

Most people, I suspect, would plump for the happiness option, but how wise would that be? Not very sage-like, according to some people.

Straight-laced scientists have come to the drastic conclusion that happiness can kill. They say they have found that people who were full of joy as children – which youngsters are meant to be, aren’t they? – died younger than their gloomier counterparts.

Kids classed as “highly cheerful” at school had shorter lives because they tended to be more carefree, exposing themselves to danger and making unhealthy choices about their way of life.

I don’t want to depress you, but these cheerful chappies and chapesses were more likely to suffer from mental problems such as bipolar disorder, perhaps leading to extreme mood swings.

And trying to do something about it can make matters worse, it seems. Being too cheerful could prompt anger in others. That must be the old “what are you smiling at?” syndrome.

It does not get any better. A study concluded that volunteers who followed tips in magazine pieces on how to be happy were often left feeling far worse than when they started. Is there no end to this misery?

Well, yes, there might be. According to a Yale University professor, the key to true happiness is simple: meaningful relationships with friends and family.

Over at Harvard University, other researchers with a much brighter outlook on life have been telling the world that everybody wants to be happy and everybody knows they should be happy.

Their scientific study trumpets the finding that happiness improves productivity by 30 per cent, that if you are happier before you do a task, you increase your chances of success and speed by up to half, optimistic sales workers outsell their negative colleagues by 56 per cent, happy employees show three times greater creativity in their work, and happier GPs diagnose more accurately and intelligently 19 per cent faster than those in a neutral state.

That sounds like wonderful news to me. It certainly brings a smile to my face.

What I particularly liked about the second bit of research was one of the main conclusions which was diametrically opposed to the theme of the first study.

This states in a very positive fashion that happier people can live up to 20 years longer than unhappy people.

Something I will not be putting on my Christmas wish list is a product which a Spanish company aims to market later this year.

It has developed a “death test” which it claims will show people how long they have to live. Why on earth would they want to know that?

Costing a whopping �435, it is a blood test which is said to accurately measure the length of a person’s telomeres (sections of DNA that cap the ends of chromosomes) which are thought to be linked to longevity.

I think I would rather live in blissful ignorance.