Have you ever lied to a mental health professional (psychologist, psychiatrist, counselor)?

My mother was a crazy and violent person. But whenever I took her to a psychiatrist, she would lie to them, often making it look as if I were the crazy one,and they always believed her and not me, even when I had hard evidence of her behavior, like medical records and police reports.

So, have you ever deliberately kept the truth from a mental health professional? Why did you do it? What did you fear would happen if you told the truth? Were you believed?