h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I've often wondered if there's a link between SAD and colourblindness, or at least whether people who are colourblind are more likely to suffer SAD and other forms of depression.

I'm about as colourblind as a person can be without seeing totally in grey scale. When people are talking about how beautiful all the autumn leaves look, I can't see the colours, so it all looks pretty much the same to me. During the winter months, and especially when driving at night or in bad weather, I can hardly tell where the road stops and the verge starts. On dull days in the summer, I can't see poppies in hedgerows unless I'm really close to them, whereas my wife can spot them a mile off.

The point I'm trying to make is that to a person who's colourblind the world is a pretty dull place visually, unless it's brightly lit. Try to imagine seeing everything that is orange, red, brown, green or yellow, as various shades of one colour. The precise colour would probably be what you'd get if you mixed all of those colours together, then varied it by adding black or white. Blue, purple, mauve, pink, grey, and some shades of red also merge into one colour too.

In bright sunshine I can distinguish fairly well between all of the colours, and that obviously makes me happier. I don't know whether I suffer from SAD or not, but I definitely feel better on sunny days, and I can't bear working in gloomy conditions.

It might be interesting to conduct a survey to see what proportion of SAD sufferers are colourblind. Any views?

I'm not colourblind but I have always had a sensitivity to bright light. Even on days which are overcast I can sometimes find it too bright and need to wear sunglasses, which usually draws remarks from other people, which in turn does not help if I'm suffering from SAD (feeling down, low self-esteem, not wanting to go out, etc). So perhaps there is some link to the physiology of the eye and SAD? There is some suggestion that SAD runs in families too, but whether this is genetic or environment-based is uncertain. Depression is also thought to run in families but this could be due to the 'negative' environment in which children of depression sufferers are raised.