ChatGPT doesn't cause a significant number of suicides. Why do I think that? It's not visible in the statistics. There are effective ways to prevent suicide, let's continue to work on those instead of giving in to moral panic.
What actually causes suicide is really hard to pinpoint. Most people wouldn't do it even if their computer told them to kill themselves every day.
My personal belief is that at some point in the future you might get a good estimate of likelihood that a person commits suicide with blood test or a brain scan.
Would the same hold for other forms of communication and information retrieval, or should only LLMs be perfect in that regard? If someone is persuaded to commit suicide by the information found trough normal internet search, should Google/Bing/DDG be liable?
Do you believe a book should be suppressed and the author made liable, if a few of its readers commit suicide because of what they've read? (And, before you ask, that's not a theoretical question. Books are well known to cause suicides, the first documented case being a 1774 novel by Goethe.)