Saddest thing about Blue Monday is the bad science

TODAY is Blue Monday, the single most depressing day of the year, if you believe the pundits. But while some journalists and retailers like to analyse and exploit the gloomy date, critics dismiss the scientific formula behind the concept as "farcical pseudo-science".

The Monday of the third week in January was first named 'Blue Monday' in a 2005 publicity campaign for the TV programme Sky Travel. It was supported by an equation devised by Cliff Arnall, a British "psychologist and life coach", which claimed to 'prove' it was the saddest day of the year.

Arnall's formula uses variables including levels of debt, time since Christmas, bad weather, low motivational levels and "time since failing our new year's resolutions" to identify the bleakest day of the year. But the result is not just "unscientific" says The Guardian's Dean Burnett, it is "gibberish, bilge, rubbish, crap, stupid, and any other polite way of saying 'utter bollocks' that you can think of".

Despite its origins as part of a marketing campaign and the fact it has been widely rubbished by the scientific community, Blue Monday has become an evergreen story for journalists. For example, the Daily Mail suggests we will "feel at our lowest ebb" today. "For the 24 hours of Blue Monday we will just have to grit our teeth and have an early night," the paper says.

The Daily Telegraph is one of several newspapers offering its readers "ways to cheer yourself up". Its list of Blue Monday remedies is written by Dr Brooke Magnanti, the academic formerly known as call girl blogger Belle de Jour, and includes getting a hobby, investigating spirituality and buying a puppy.

Retailers also "love" Blue Monday, says the Guardian, noting that Topshop is urging shoppers to "banish those blues" today by buying some new clothes. Juice manufacturer Innocent is also riding the Blue Monday bandwagon with a list of "feelgood" films to help banish gloomy feelings and Channel 4 provides a list of cheerful pop songs, books and films despite its admission that the Blue Monday formula is "much hyped and much ridiculed".

Meanwhile, Labour MP Diane Abbott has used the anniversary to score some political points, tweeting that "many days feel like Blue Monday with Cameron as PM".

The Guardian's Burnett says there are ways that people who feel "genuinely depressed" can be helped. "But for the record, nonsensical equations are not one of them." ·