On Mental Disease

Many members of my family have been diagnosed with mental disease, mostly bipolar, but I am wondering... Is it chemical imbalance or just chemical diversity? Is it just that there is more variety to normal than the psychologists want to admit? What if normal included those who live a roller-coaster ride of life, or normal included artists and writers? Maybe instead of making everyone flat and featureless psychologically speaking, with very powerful medication, we can learn how to integrate them into our lifestyle, and help them have happy, healthy, and at times more and then less productive lives.