In this discussion, a human has studied psychology and has diplomas or certifications to prove it, an ethics framework it must follow, and responsibility for its mistakes. ChatGPT has none of that, it just regurgitates something it got from the Internet's wisdom or something it invented altogether.
I'm not saying humans are never wrong, but at least their reasoning isn't a black box unlike ChatGPT and other LLMs.
Additionally there's something called the replication crisis in the social sciences (psychology included) which is basically to the effect of a major discovery that most of these "black box" studies can not be reproduced. When someone runs the same experiment the results are all different.
It goes to show that either many of the studies were fraudulent, our statistical methodologies are flawed, both.
Given that chatGPT therapeutic data is ALSO derived from the same training data I would say it's ok to trust chatGPT as much as you would trust psychologists. Both have a lot of bullshit with nuggets of truth.
What if you talk to a human, and their advice is wrong or makes you worse off in the long term, because they're just repeating something they heard somewhere?
Here's my advice: Don't accept my advice blindly, humans make mistakes too.