I've written before, on the nature of tragedy. Characters advancing their course without the development necessary to prevent an ill-fated end.
Mental illness, in that case, is by nature a tragedy. It prevents development by subsuming someone in an alternate reality. And depending on severity, it can be sheer luck that the sufferer is diverted from an ill-fated end.
We have no system for recognizing, diagnosing, or treating the mentally ill. Currently we rely on the mentally ill and their loved ones to recognize, and hopefully push for diagnosis and treatment - of conditions that may not even be tangible. Barring that kind of prescience or luck, what we have are a lot of tragic characters, wandering around coping, ill-developed, ready to enfold others in their tragedies.
It only sounds melodramatic until it happens. I had no system for recognizing any kind of mental illness, except for the obvious and tangible. And the line for obvious and tangible is shifty, depending on the types of people one has interacted with in the past and the norms of behavior thus derived.
Reclusive, stubborn, vague, inconsistent. I have known all of these to varying degrees - so how do you know? There is no checklist, and even if there were, I wouldn't subject everyone who came into my life to a pre-screening. But how else can you tell if someone's norms for behavior are entirely in their head?
I assume, of course, that if I had known, everything would be different. That recognizing would render diagnosis and treatment (and possibly development) faster. But knowing would only have changed my behavior (I would have been less angry) and wouldn't have changed his (so I would have been just as hurt). But mutual recognition - I wouldn't have struggled alone, we would have struggled together. It would've made all of the difference, except I was too naive and he was too much into just coping.
I am still so angry, to have ended up just as alone as I'd always been, despite all of that trying.