Health: Clarity in a cold climate

Ever wondered why artists produce their best work in freezing garrets? Contrary to long-held views, rather than slowing down in the long dark days of winter, people are brighter and quicker. So can we cheer up now?

Bidge Hansen and his neighbours in the world's most northerly university town spent yesterday pretty much in the dark, again. It may have been one of the shortest days in Britain, but in Tromso, 200 or so miles north of the Arctic Circle, it was yet another day when the sun failed to put in an appearance. Between 21 November and 21 January the Norwegian town and its 60,000 population live life in a permanent night, and in the summer they switch to spending months in perpetual daylight.

For psychologists, the extremes in this Arctic Circle environment made it the perfect place to study the effects of the seasons on the mind and on performance, and to investigate whether there is any foundation for long-held views that in winter, human thinking, memory recall and performance slow down. If the theory was right, any effect would, they figured, be magnified at a latitude of 69 degrees north.

For more than a year doctors tracked volunteers, measuring their cognitive performances in tests in both winter and summer, fully expecting the results to support the view that in winter people are prone to suffer a range of negative symptoms, in addition to the depression associated with seasonal affective disorder (SAD).

But when measured by cognitive performance, it was found that the people of Tromso were brighter and quicker in the winter months, a result that puts a large spanner in the works of those who hold that man is mentally duller and slower in the winter. For Dr Tim Brennen, who led the research and who briefly escaped the winter blackness of Tromso University this week to present his findings at the London conference of the British Psychological Society, the results were a big surprise.

"We tested 100 people on a battery of cognitive tests, including memory, attention, reaction time, memory recall and confusability. We didn't look at depression, we were only interested in cognitive performance. We tested them in summer and in the winter, and we were sure that we would be able to pick up the winter deficit that is so often talked about,'' he says.

"If you read a lot of the literature on SAD, the biological psychiatrists expect concentration to be worse in winter, that speed of thought and memory will be poor, and that people will feel sluggish. But we found no trace of that. Clearly the belief that people get groggier and more forgetful in the winter months is unfounded. The findings contradict some of the claims found in the literature on SAD.''

Even on the simplest of the tests - measuring reaction times to a circle being flashed on to a computer screen - the winter performances were better. The reaction times of the volunteers were on average 11 milliseconds quicker in the winter tests. The problem that Dr Brennen and his colleagues now have is explaining what kind of body mechanism could possibly be at work to produce the unexpected phenomenon of superior thinking in winter. It is at odds with many assumptions about health and the winter. A National Institute of Mental Health survey of 1,500 American SAD patients found that more than 90 per cent reported decreased activity in winter, as well as difficulties with work. They also reported extreme fatigue and lack of energy, and an increased need for sleep.

SAD, which affects between one

and 25 per cent of people depending upon which study is looked at, is accepted as a condition where depression is linked to the arrival of winter months. But depression and improved cognitive performances are strange bedfellows, so the hunt is now on to find out what could be happening in the brain to produce such a paradox. Investigators are looking at whether light or temperature, or even some other trigger, may be at work.

Some suspect that a change in the environment, especially the arrival of long dark nights, affects personality - that when it gets cold and dark man becomes more introverted and more focused on the tasks in hand.

"It is a quite surprising and counter-intuitive finding that requires a lot of thought,'' says Professor Anne Farmer of the Institute of Psychiatry in London, who specialises in treating affective disorders, including SAD.

"One possible explanation is that we are less distracted by other things in winter. There is not so much to look at and therefore a greater opportunity for you to attend to your tasks.''

For the treatment of the depression associated with SAD, Professor Farmer and an increasing number of doctors are advising using light boxes. It's been found that exposure to bright artificial light can substantially reduce the symptoms of depression by as much as 80 per cent in some patients. Research on people with SAD has also found that their symptoms improve the nearer they get to the Equator.

But just how light works is not clear. "Although the cause of SAD is not known, research so far suggests that it is triggered by a seasonal disruption in the cycling of the hormone melatonin, which throws the circadian rhythms off balance,'' says Professor William Regelson of Virginia University and author of The Melatonin Miracle.

"Research has shown that melatonin levels are abnormally increased in people with manic disorder, and yet are abnormally low in people with some kinds of depression. There is in fact a low melatonin syndrome in depression which is characterised by low melatonin levels and disrupted circadian rhythms governing the production of hormones.''

And hormones may be implicated in the mechanism behind the Tromso results for cognitive performance, because a similar finding of depression and an improved or unaffected mental performance is found in one other body cycle.

Researchers who have studied the monthly menstrual cycle have found that while it has an established effect on mood, cognitive performance is either unchanged or improved, just as Dr Brennen found in the annual body cycle in Tromso.

More investigations into winter supremacy are now likely, and researchers want to look at the links between the seasons and the great thinkers, writers and inventors. Did Einstein and Newton have greater successes in winter, and were the Brontes and Dickens more prolific when the days were shortest?

Professor Helen Phillips, professor of English studies at the University of Glamorgan says that, yes, the Brontes did produce in the winter. At least three novels were written in this season. Dickens, on the other hand, says professor Stephen Knight of the University of Cardiff, wrote all the time. His driving force was more down to earth than the changing seasons: it was deadlines.