All sickness, accidents, lack etc., anything that isn't love, joy, peace, patience, kindness, goodness, gentleness, faithfulness and self control must be from the adversaries realm. "Chemical imbalance" is not from God, it may be the smokescreen the adversary uses to hide His attack on health, and medicine might help but never sent anyone to the Dr. , He never said "this ones too tough for me", the Gettering (sp?) demoniac included.
Out of His kindness He may allow Drs. to help some, but we must NEVER place them above or give first place over Jehovah Rapha, the God who heals us.