You can only get out of a contract for mental health reasons IF you can show that at the time you signed it, you were so impaired as to not be mentally competent and therefore lacked the legal capacity to contract. Mental health issues falling short of rendering you legally incompetent do not impair a contract; and anything occuring after you signed/agreed to the contract does not affect it, either, because if you were competent to sign it, you are then bound by/to it.