It’s not very often we get to talk about a revolution in understanding and treating depression and yet now doctors are talking about “one of the strongest discoveries in psychiatry for the last 20 years”.
It is based around the idea that some people are being betrayed by their fiercest protector. That their immune system is altering their brain.
The illness exacts a heavy toll on 350 million people around the world, among them Hayley Mason, from Cambridgeshire:
“My depression gets so bad that I can’t leave the bed, I can’t leave the bedroom, I can’t go downstairs and be with my partner and his kids.
The 30-year-old added: “I can’t have the TV on, I can’t have noise and light, I have suicidal thoughts, I have self-harmed, I can’t leave the house, I can’t drive.
“And just generally I am completely confined to my own home and everything else just feels too much.”
Anti-depressant drugs and psychological treatments, like cognitive behavioural therapy, help the majority of people.
But many don’t respond to existing therapies and so some scientists are now exploring a new frontier – whether the immune system could be causing depression.
“I think we have to be quite radical,” says Prof Ed Bullmore, the head of psychiatry at the University of Cambridge.