In the first of our extra mid week treats, we open our bulging sack and display it for all to see: we will talk about a new theory of depression linking it to a physical reaction to infection, taking the best bits from CBT and tackling the guild some people feel in how they have tried to help with the suffering of someone they love.

This is "Why the long face?" in which we lift the lid on depression in a sometimes lighthearted and always non-judgemental way.

It is a conversation between two old friends, usually over a drink or two.

Paul has been a psychiatrist for 20 years and has done years of research into mood disorders and Oliver is a business consultant who has dealt with a lot of depression and its consequences in the workplace.

Cheers!