Little Busters! - Riki Naoe Character Discussion

[Pepe]

I would like to talk about this point made in another topic:

Little Busters! - Refrain Arc Discussion

Saving everyone was impossible precisely because, if Riki stayed behind, his fear of loss would trigger his narcolepsy, thus knocking him out and Rin would be too shaken up to be of any help.

Did they ever really explain what exactly triggered Riki’s narcolepsy? I didn’t seem to quite get that, and if they did, then this is just me asking a simple question