Depression seemed to be talked about more last year than in previous years thanks to celebrities revealing their troubles with the affliction. There’s also been more research into depression. With more people thinking about and looking into depression we get new perspectives on the issue.
Now, some researchers are arguing that depression could be a symptom of lifestyle decisions and some influence from our evolution. The evolution aspect is rather interesting because it could be interpreted that depression is a reaction to help one person not infect others with communicable diseases.
So if people with depression show classic sickness behaviour and sick people feel a lot like people with depression – might there be a common cause that accounts for both?
The answer to that seems to be yes, and the best candidate so far is inflammation – a part of the immune system that acts as a burglar alarm to close wounds and call other parts of the immune system into action. A family of proteins called cytokines sets off inflammation in the body, and switches the brain into sickness mode.
Both cytokines and inflammation have been shown to rocket during depressive episodes, and – in people with bipolar – to drop off in periods of remission. Healthy people can also be temporarily put into a depressed, anxious state when given a vaccine that causes a spike in inflammation. Brain imaging studies of people injected with a typhoid vaccine found that this might be down to changes in the parts of the brain that process reward and punishment.