Good luck. I did some and found it helpful. I kind guess personally that it works by a kind of neural network rewiring. Before CBT some neurones are taking input, processing it as indicating things being crappy and directly signalling that to the older reptilian bits of the brain that deal with that, without conscious awareness. By consciously becoming aware of the things are crappy reasoning you can argue against it and rewire those networks. At least that's my theory on it.