Popa, I think you are lacking a basic understanding of CBT. Anxiety or depression aren’t causes by negative behaviors or thinking. They are most likely biological illnesses. But their symptoms manifest in physical behaviors and thoughts. CBT is not about curing mental illness. It’s about managing the symptoms. Once you’ve mastered that, there isn’t much else to do.
Of course, there are plenty of cases that require medication. But this does not mean that the symptoms are unimportant in treatment.