It comes like a weather forecast
Announcing rain.
You are unsure if or when or how it will come.
People will show you the signs to look for,
To make, at best, an educated guess
Of what will happen.
It may come as a slow and steady fall,
Lasting for days, not too difficult to live with,
But persistent.
It may come as a brief but brutal downpour,
Keeping you locked inside your house alone,
Waiting for it to end.
Only an hour may pass, but you know it has affected you in some morbid way.
You may wait for it come, because you detected all the signs of its arrival, only for it to decide now to show up at all. You will take a deep breath and be thankful.
There are no signs to guarantee
If or when or how
The rain may come.
There are no signs to guarantee
If or when or how
The depression may come.
You await the next warning from the weatherman.
You await the next warning from the therapist.
You look for all the signs.
But you never know
If or when or how…
Maybe I'll Just Write Poetry 
A beautifully powerful piece of writing.