PCOZ, chemical balance is not for psychological therapy. For that one needs medication.
Self confidence is the normal, natural emotional state of not having negative feelings about yourself. The Chovos Halevavos says that the kind of Hachna’a that comes from actually being week and subdued is not a special Mida. That is like the animal in a yoke, that happens to be aware of the fact that there is a yoke over him. An Oved Hashem has a Lev Nishbar, knowing that he does not come close to completion, and has, alongside that, a great Simcha and positive disposition, realizing his great purpose and aware of his abilities.
Self confidence is about realizing your abilities, not your achievements. Realizing achievements may help you to realize your abilities. Lack of self confidence is not a Maala in any sense.