Seasonal Affective Disorder

Christmas really depresses me. As a scientist, I am driven to understand this problem, and, of course, to fix it. This year I’m still far from enlightenment, but I think I may be within sight of a cure.

It haven’t always had the problem. Forty years ago Christmas was the glittering pinnacle of joyous excitement standing out above each year of tedium. I can remember as a five-year-old yearning desperately for the dawning of the great day, or rather for the visit of Father Christmas, who always passed through my bedroom sometime between midnight mass and breakfast time.

As a catholic, I had an unshaking faith in Father Christmas. I never doubted his existence for a millisecond. Indeed I met him a couple of times during my childhood. In the flesh he was quite disappointing, unispiring, slightly repellent – nothing to write home about at all. But this was a false impression which was completely dispelled by my written correspondence with him. He never failed to come good on the big day and to respond generously to my written requests. My faith in his capacity to deliver the goods brightened up the whole of December.

I can’t remember when Christmas lost its charm. Of course its significance as the annual festival of gratification evaporated when I acquired credit cards and gave up religion. The giving and receiving of presents evolved into a time of social anxiety and atheistic embarassment. But the depressing character of the festive season is far more pervasive than that. Its roots must be deep in my psyche – or possibly in my biology – let’s look.

Psychoanalytic explanations for depression at Christmas are disappointing. Desire for a penis evoked by the tree, memories of unresolved sibling rivalry evoked by the child. These definitely do not apply to me.

I come from a large family, so I should explain why I reject sibling rivalry as an explanation. It’s not that discord did not ruffle the calm waters of my happy childhood. But as an explanation for Christmas depression it’s a non starter. It doesn’t come close.

The reason is simple. There were no calm waters in my childhood. It was a hundred years war of internecine sibling conflict . Did you know, mathematically, a family of eight children can have over 5000 separate two-way arguments at once? I didn’t need maths to tell me that. I was there. In fact if you form – and break – alliances you can increase the possible number of disgreements to tens of thousands. We did. So I don’t need a once-a-year symbol of a baby to evoke bitter memories of lost childhood battles. Those memories are with me every day!

Biology provides more realistic explanations for winter blues. {As Clive Cookson, science editor of tthe Financial Times wrote in this column two weeks ago,} we are a complex network of interlocking biochemical clocks and calendars. We wake and sleep on a regular cycle driven by the rotation of the earth. The annual cycle of the seasons drives an internal calendar.

In many plants and animals reproduction is seasonal. The regular annual variation in the day length drives hormonal changes that prime the reproductive organs – and the reproductive aspirations – of many species. The brain’s chemical messenger systems that control mood are also affected.

We are not seasonal breeders, but we share a lot of our biological and neural machinery with our animal relatives. Our brains contain much of the same clockwork. It is no great surprise that there is a recognisable depressive condition in humans that comes on in the winter. Seasonal affective disorder, SAD as it is known, seems to be triggered by the change in amount of daylight. Christmas, four days after the shortest, darkest day of the year is boom-time for SAD sufferers.

SAD has been recognised for about ten years now. In the US it affects up to 10 per cent of people in frosty New Hampshire and only 1.5% of people in sunny Florida. The interesting thing about it is that short periods of exposure to intense light – even artificial light – lift the depression in many sufferers. Others respond well to modern antidepressant drugs like Prozac, that increase the availability of the chemical messenger serotonin.

Serotonin is involved in brain systems that regulate mood, and is also involved in regulating biological rhythms. Many SAD sufferers also show minor abnormalities in the way they process serotonin and it seems that these may an important cause of SAD.

My personal Christmas depression is different from SAD. It is focused on the festivity itself. For me winter would be a brighter prospect if its gloom were not disturbed by the bright lights and enforced conviviality. So I am pretty sure that neither light treatment nor Prozac would help me.

But do not worry: I think that I have a cure. Father Christmas delivered it last week: two plane tickets to Santa Cruz de la Palma in the Canaries. We fly out tomorrow. ¬°Feliz Navidad!