I'm reading an article about suicide on the website 'NPR', but I don't understand the meaning of this sentence.
It's really when the symptoms add up in the mind of that person, where they think 'The way I deal with this is to take my life.'
This is entire paragraph including the sentence for your understanding.
"Some of the warning signs would certainly be depression and ... loss of concentration. People not seeming like themselves. Insomnia can be a big risk factor. Other warning signs might include irritability, withdrawal. And the thing that's really critical: Lots of people have those symptoms and are not thinking about suicide. It's really when the symptoms add up in the mind of that person, where they think 'The way I deal with this is to take my life.' "
The sentence I don't understand is the last one.
You can see the whole article here. http://www.npr.org/sections/ed/2016/09/02/478835539/6-myths-about-suicide-that-every-educator-and-parent-should-know
I understand what each word of the sentence means, but I don't understand the structure 'It's really when ~~, where ~~ .'.
Please let me understand the meaning clearly.