Personally I never called any such hotline; my assumption was that suicidal thoughts originate from one's own brain and way of thinking - adjust that and these issues would go away. Unfortunately, while this can work (for me it worked extremely well, though I should also say, I don't have suicidal thoughts to begin with, even more so as one's lifespan is finite anyway - but I do understand those who have a terminal illness, to not have to go through more suffering when something is uncurable), there are people for whom it can not work, often in the way how their brain works. Just like some people have seizures, brains are different too.

It puts some responsibility on those who receive such calls, because the caller may be in a state where any additional negative input could push that caller over the edge, due to their current state of mind. So this kind of requires more training even of casual people, just as people are expected to know the basic steps necessary for first aid (on a fresh accident site, for instance). It seems pretty clear that those on the national hotline, must have had professional training too. So if there is a decline of suicides, this is most likely - and logically - due to the work by those who take up the phones.