If mental illness is stigmatized in your society, then your diagnosis or lying about it on a job application could jeopardize your job or your career; however, unless you somehow call attention to yourself, the education and health ministries might never communicate and reveal your secret. If and when it's ever discovered, your diagnosis could well be mitigated by your exemplary performance as a teacher, and your deception in your application could fairly be attributed to your fear of job discrimination due to the stigma associated with mental illness. If you're already an intern after falsely denying a diagnosis of mental illness, you've already gotten away with it. Trust no one with these secrets and you'll be fine.