To quote from the Google TOS that everyone has to adhere to, " Google doesn't allow the promotion of self-harming or violence against people or animals, such as suicide, pro-anorexia or bulimia, and street violence."
Or it is more clearly stated here..."Google doesn't allow "anti" or violent concepts, such as the following: ( about four bullet points down the page ) The promotion of self-harm and violence against people or animals."
Remember it is not hubpages TOS but Google's TOS that decides if your hub will run ads on it from adsense. Unfortunately there aren't a lot of good synonyms for suicide, if the word itself is the problem...which I doubt.
Suicide - noun self-murder , hara-kiri , mélange , self-destruction , self-immolation , self-slaughter or seppuku.
Ugh, what a bunch of icky choices I know.
(If you are using the words Suicide Prevention/ putting a hyphen might get by the problem aka Suicide-prevention...another alternative might be saying killing yourself, or killing themselves, I don't know what your title is, but for example...Killing Themselves is Not the Answer, or Don't Kill Yourself, etc. Not probably what you want, but there are creative ways to get past certain grey areas. Have you considered calling it something neutral and writing the article, without ever saying suicide. Just say alternatives like I have addressed already..?)
If suicide is in the title, changing that maybe enough to get by the Google rbt txt...but again I am unsure. I would be interested to know for my own writing purposes. I had the same problem when I tried to write and article on artificial intelligence and robotics, because the subject matter was realated to technosexuality, which red flags as high tech pornography. Go figure.
Maybe something I have ranted about here can help you, good luck. Keep on hubbing. Blake4d