It's becoming less effective over time
https://pubmed.ncbi.nlm.nih.gov/25961373/counter meta-analysis that claims the opposite:
https://pubmed.ncbi.nlm.nih.gov/28230413/. I lean towards believing the first based on MUH GUT because I cannot believe that CBT works on anybody who isn't completely fucking brain dead so there has to be diminishing returns as to expose more of the population to it.
I've been diagnosed with anxiety from a young age and CBT is the biggest and most condescending meme I've ever been exposed to. Probably the most recommended book in the space "Feeling good" takes the philosophical position that thoughts that make you feel bad are inherently invalid.
Every CBT advocate pushes stories about how some multimillionaire CEO with a hot wife who jet-ski'ed for a living was feeling glum, and said "my life is terrible, I lost this business deal, I screw up everything", and then the doctor would say "Actually, you are very successful, and do many things right" and then the CEO would go "wow I didn't think of things that way!" and be fucking cured just like that. Literally everybody in the field fundamentally believes everybody besides them are retards and that's why they're not happy. I quite like the snide rebuke to medicalism like CBT such as "shit life syndrome"
https://www.theguardian.com/commentisfree/2018/aug/19/bad-news-is-were-dying-earlier-in-britain-down-to-shit-life-syndrome which while hardly /sci/ points out that blaming people for feeling like shit when they live shitty lives is mostly a form of institutionalised victim blaming and that if you genuinely want to improve peoples depression and anxiety you have to meaningfully improve their lives not go "LUL YOU'RE IRRATIONAL YOU'RE LOOKING AT THIS THE WRONG WAY :^)"
I do a bit of third wave therapy but it mostly seems like a waste of money, but it's my employers money :^). At least it isn't quite as bad as a condescending meme.
P.S. CBT usually does not work.