To the best of my knowledge, St. Dymphna would be the patron saint you are looking for. The Church does not have separate Saints for the different disorders, so she would be considered the Patron Saint of those who suffer from Mental Illness. Here is her page in the Catholic Encyclopedia, courtesy New Advent:
I hope this helps, and I encourage you to continue your treatment with Faith and Fidelity. Allow both Divine and human treatment to work together. I wish you the best.
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