The above quote, I think, is a poetic and emotionally truthful way of thinking about depression, but ultimately, it may not be a scientifically accurate picture.
Scientifically, it may well be the case that depression is caused ultimately by inflammation. As that article says:
The basis of this new view is blindingly obvious once it is pointed out: everyone feels miserable when they are ill. That feeling of being too tired, bored and fed up to move off the sofa and get on with life is known among psychologists as sickness behaviour. It happens for a good reason, helping us avoid doing more damage or spreading an infection any further.
If this is the case, avoiding depression may almost become trivial. That would be a great world, don’t you think?
The Complete History of the Universe: A Personal Journey 