On Mental Imbalance

I don't know how much my experience can speak for other people, but I have a hunch that, like me, almost everyone on the planet has at one time or other wished desperately for an escape, struggled with darkness closing in. Sometimes it feels like there is no point in our existence, that we are uncared for, accomplishing nothing, misunderstood, overwhelmed by doubt, fear, guilt. Another day and another day and another day after that, all painful and all the same, all leading to what? For some the mental challenge of despair is perhaps greater, as they are tortured by obsessive thoughts, be they about food or a need for super-imposed structure, extreme highs and lows, or irrational fears, actions caused by desperate need to make sense of what seems so senseless or lash out from a perspective outside what most people claim as theirs.
My brother was diagnosed w/ OCD and some more distance relatives of mine w/ being bipolar. I know people who've struggled w/ anorexia or bulimia.
I believe it is possible for medical diagnosis and assistance for mental problems, similar to that of medical help for asthma but I do also believe that mental problems may be more complicated and harder to help. For one, we are wonderfully complex, made in the image of God, and our ability to think is a reflection of who God is. We can imagine something other than what is but we cannot always achieve it. We can recognize the dichotomy between what is and what we feel should be. Even for those whose thinking is not labeled as skewed, thinking can often lead to frustration. Life on this earth, under the sun, falls short. Read the book of Ecclesiastes and recognize the sadness of this dissatisfied, searching wise man who even as he learned satisfaction was found only in God, struggled w/ the reality of dissatisfaction present to a degree even in the life of a believer, under the sun. It's interesting that a connection between genius and madness is often posited. Perhaps it's because madness is all about thinking. While thinking is a beautiful thing, because again, it's a reflection of God, it's also horrific w/o God, and is tainted by sin, even at its best, as is all of the world we live in.
God allows despair for a reason. Great theologians and hymn writers such as Spurgeon and Cowper struggled with depression, times when they were virtually incapacitated by it. In our despair, we must cling to our God, trusting sometimes blindly in Him. He will one day put all to rights and in the meanwhile, as long as we are here, He has something for us to do.