I had CBT for a few weeks for agoraphobia, generalized anxiety disorder with panic and mind depression.
I liked the idea of CBT and I got some great advice from the psychologist. But after I felt I got all I could from it (after about 4–5 sessions) I stopped. And the reason I stopped was because the psychologist I was seeing, wasn’t open to any other psychological theories. So what could have been improved with a combination of CBT and behaviorism, was only met with repetitive CBT exercises. When I mentioned behaviorism it was quickly dismissed and put to the side. So I stopped CBT, but I did benefit from it.
Edit: Additionally, I had online therapy that combined CBT with behaviorism, mindfulness, and other things that helped me a lot. So I think CBT is great, and it works, but I think it is more effective (for me anyway) when it is combined with additional theories.