PAUL DAVIS One evening, during the first 10 days of 2001, I was listening in a desultory way to Virgin Radio. It was a show that allowed listeners to call up and request a song for their wives, husbands etc. A pleasant and reposeful guy, probably in early middle-age, called. The faintly upstartish host asked him how he was and what he was doing with the evening. He said he was great, thanks, and that he was making a meal for his wife.

"But aren't you suffering from the post-Christmas blues and that?" beseeched the clearly peeved host. "No, my life is wonderful," rejoined the caller. The dialogue trickled away, the caller requested and got the song, and the host followed with some defensively sneery comments about the blameless caller.

The anecdote provides a salutary counterpoint to a social phenomenon now almost as formalised and mandatory as Christmas itself. The annual emission of articles, features and allusions confirms it: the "January blues" is unavoidable. Indeed, in 2005, a team of "researchers" with too much time on their hands announced that Monday, January 24 ("Blue Monday") was the year's most depressing day (the equivalent announcement followed in 2006).

However, like many an inevitable thing, the January blues are entirely avoidable. Indeed, they are needless and nonsensical.

Lack of daylight is one of the explanations put forward. However, there is no good reason why limited daylight should have a particularly undermining effect on us. A great many of life's goods remain available during winter, and some assume, indeed, an aesthetic mood that should be just as compelling as that assumed the rest of the year (consider activities that cross the seasons, for example football). Also, if limited daylight is the problem, January should not be the most difficult month. Lengthening days become detectable very soon after New Year. It would be more rational to respond negatively to November and December.

The stock reply to the last point is that in November and December Christmas has yet to happen or is happening, while in January it is gone. This seems, at first blush, quite sad, and it is tempting to reply harshly that anyone thrown into depression by the end of the festive period needs to get a life. However, what very few sufferers seem to entertain is that the festive period is itself a huge part of their problem.

By mid-December, most of us could do with a break. This probably owes less to the weather or to darkness than it does to the normal pressures of life, especially work. However, if we set out to draft an agenda that would leave us worst equipped to return to the fray in January, we could scarce do better than the festive period as it typically manifests itself in the UK.

There are too many detrimental qualities to cover. An entirely stress-free Christmas is probably unavoidable and undesirable (as is a stress-free summer holiday). But stress levels are well beyond what is necessary. The approach to Christmas is full of needless anxiety for most, in the form of present acquisition and related expenditure.

Need you really buy for the in-law you never see and don't like, and who doesn't like you? Does he care what you get him? If you really must, is there any good reason why a small gift voucher won't suffice? Is it vital that all presents and cards get to recipients for Christmas? Will they be bothered? And do you have to resign yourself to a ghastly January credit card bill? The answer to all of these questions is no.

And then comes Christmas itself. One of the many ironies is that what is supposed to be an affirmation of life (eternal life, no less) typically smells of death-in-life. Greed and consumption, in a context of exaggerated social pressure, puts most people into a dopey, irritable stupor on (at least) Christmas Day, Boxing Day, Hogmanay, New Year's Day and January 2.

Most feel that this is obligatory but it is, again, avoidable. All that sustains it is habit and a certain lack of fortitude. You don't need to see all of these people on these specific days. You can explain that you won't quite make it round until - perhaps - the 28th.

Generally, they will understand, and if they don't it will have to be their problem. You don't need to eat and drink until you flop on to a couch and try to keep your bleary eyes fixed on an annoying comedy you've seen umpteen Christmases before. It is entirely within our gift to stop eating and drinking long before we do.

It is similarly possible to avoid stultification in front of a television, and to opt instead for a bit of something that one would normally do and enjoy, such as a walk, a cycle, a book - or even a bit of work. The festive period we typically have seems designed not to recharge batteries but to mercilessly squeeze any remaining charge from us, leaving us facing January in a state of pent-up torpor.

The previous year's frustrations are not discharged or managed, as many touchingly and forgetfully assume they will be, but are instead heightened. Few seem to make that connection, and express the same indignation year after year about their old friend, the January blues. The solution is, as ever, prevention. But prevention in this case is remarkably easy.

For around two decades, I have loved January. It helps that I like darkness. But more relevant is the fact that I tend to have the kind of Christmas that I want, and therefore feel as refreshed as I do on return from a summer holiday. I consume a little more than usual, sure. There is some stress, sure. But the analogy with the obligatory Christmas ends there.

I no longer eat or drink to excess. I don't have futile worries about "seeing everyone" or buying for all and sundry. I keep myself generally fit and healthy, and neglect nothing that really matters to me, including work.

The result is that it is now so long since I suffered the January blues that I wouldn't recognise them if they crossed the street in front of me. I had a great Blue Monday last year, but hey, thanks for asking anyway.

I look forward to the most depressing day of 2008, when I might phone Virgin, ask that dodgy host if he is suffering from post-Christmas blues, and tell him how I'd love to hear the Boo Radleys singing Wake Up Boo Paul Davis is a philosophy tutor at Edinburgh University and a Scottish football fan.