If you suspect that your ex is providing false information to a psychiatrist or any other professional in order to influence a custody case, it may be a matter worth discussing with your legal counsel. This situation could potentially be considered perjury, which is the act of intentionally providing false information under oath. Perjury is illegal and can carry legal consequences.
To address such concerns, you should consult with a family law attorney who can advise you on the best course of action. They will be able to guide you on how to handle the situation appropriately within the framework of the legal system. It may involve gathering evidence to challenge the false information presented and ensuring that the court has a clear and accurate picture of your mental and emotional health.
Remember, laws can vary by jurisdiction, and family law cases can be complex, so it's crucial to seek legal advice specific to your situation and location.