Published: 15/12/2005 Volume 115 No. 5986 Page 31

Christmas goodwill and cheer is often accompanied by elevated rates of depression and suicide. But the statistics are a bit more complicated than the media usually lets on.

There is a tendency for suicide figures to decrease before and during major public holidays like Christmas, then dramatically increase after the holidays.

The explanation for this phenomenon is termed the 'broken promise' effect by psychologists. This dip and climb has also been referred to as a tendency for 'postponement' of suicide until after a holiday. Major holidays such as Christmas repeatedly show the largest fluctuations in suicides.

The theory is that if we are feeling low about our lives, we postpone suicide or deep upset until after Christmas because we hope the holiday season, with all its promise of socialising and merriment, will help resolve or stave off our problems. But then the disappointment of how miserable Christmas can be means the 'promise' is broken, and we lapse into post-holiday blues.

The treatment for this significant problem is to not to see Christmas as a way of solving deep-seated problems, instead addressing them separately.

For example, if a relationship or work issue is proving problematic, do not just hope the Christmas atmosphere cures it.

Tackle it directly. If anything, the upheaval of Christmas can exacerbate underlying tensions - this is why fragile marriages can be dealt a knock-out blow by the festive season. Aim to see Christmas as a deadline for addressing problems, not a solution.

We tend to think of Christmas in materialistic terms; we look forward to receiving gifts, but try thinking of your time and attention as the most precious gifts of all. Donate them to those who are especially deserving. Also, it is vital not to let the media hype over Christmas stoke up your expectations - if you lower them, you are more likely to be positively surprised by what the festive season brings.

So expect the worst, and when Santa doesn't steal your computers you'll think It is the best Christmas ever.

Dr Raj Persaud is consultant psychiatrist at South London and Maudsley trust and Gresham professor for public understanding of psychiatry.