I spend about three hours weekly scanning medical and psychological journals on the internet.

Unpleasant, negative emotions can be highly functional. For example, anxious hypervigilance in a dangerous situation can keep me on my toes, very aware of potential threats and more able to react rapidly and appropriately. Healthy anger when I am being taken advantage of can help me respond strongly and assertively to protect my rights. In her book "Productive & Unproductive Depression" the psychotherapist Emmy Gut suggested that even depression can at times be functional. She wrote " ... in the wilderness in which the human race developed its current genetic characteristics, individuals who had the capacity to respond to dangerous or otherwise significant circumstances with an adequate set of emotions, and acted accordingly, had a better chance to survive, to have children, and to raise them than individuals who were deficient in that respect."

The Christmas edition of the British Medical Journal usually has a series of light-hearted articles in it. Last month's copy was no exception. In one of the articles, entitled "Medical myths" (Vreeman & Carroll 2007), the authors wrote "We generated a list of common medical or medicine related beliefs espoused by physicians and the general public, based on statements we had heard endorsed on multiple occasions and thought were true or might be true. We selected seven for critical review". The first myth critiqued was "People should drink at least eight glasses of water a day". Searches on Medline and Google apparently yielded no hard evidence supporting this advice. There are many sources stating that it's good health practice, but they could find no worthwhile evidence to back it up.

6.15am and I'm sitting in front of my computer. Berg's violin concerto is playing on Radio 3 (it's through their "listen again" feature).