I have this theory...well I'm not going to claim it's profound or even unique...but it's a theory never the less. You see, I don't think mental illness is this kind of on/off switch. It's not this condition that either exists or does not exist in us. Rather, I think it exists in all of us. Every single one of us. It's about degrees on a slope and what we do about where we are on that slope that counts.
Some of us, for reasons that are probably both simple to feel but far too complex to explain, are able to keep our mental illness in check. We manage it...which basically means we manage ourselves. We have mastered the art of turning down the volume of the voices in our head or we have learned to completely ignore them.
"You lock the door
And throw away the key
There's someone in my head but it's not me."
- Brain Damage, Pink Floyd (Written by Roger Waters)
Others, well, they never really had a chance to manage it, either lacking the basic tools of self management the wherewithal to use the tools. Mental illness manages them, and it's a tough boss. The volume button for the voices inside their head was broken off, and Radio Shack is now closed.
Still others start at one end and slide down to the other. The slide can be assisted by substance abuse or the slide can cause substance abuse. Or the despair that comes with no longer being able to buy enough stuff to sooth the profound feelings of being unfulfilled by everyday life. Or the trauma of a life change for which there was little preparation and even less understanding. I don't think that really matters so much. Sadly, the slide here almost always seems to be towards greater illness, not less.
None of the above is to say that it's hopeless. I think we all can climb the slope in a positive direction, but it helps if your not already too far down the line to begin with. When all is said and done though, I think the real core of it all lies in the acknowledgement that we all share this common bond of illness, in varying degrees. None of us are that alone, a thought that is actually pretty comforting when you ponder it.