Agree on LLMs being effective for nudging therapy like CBT. I built an obsidian plugin "ChatCBT" with chatgpt 3.5 that has really helpful for pulling me out of episodes I start to spiral in negative thinking. I'm shocked how effective this is with a basic prompt (you can see the prompt in the codebase)
https://github.com/clairefro/obsidian-chat-cbt-plugin