Work health & safety laws protect your right to a safe workplace, but you also have responsibilities under the same legislation. You must take care of yourself and others and cooperate with your employer in matters of health and safety. This applies to all workers, whether they have a disability or not.
If you're experiencing a mental health condition, you are legally protected against discrimination in the workplace. You also have a right to privacy and are not legally required to tell your employer - unless your condition could endanger you or your colleagues.