I'm not sure if this is to do with cultural differences. I'm not anticipating ever being in a courtroom in my life. I think most people are not. If I had married a very abusive partner and there was a custody battle (I have a family member who was in this situation) then I would rely on objective evidence e.g. police reports from when they had been called out. Therapy or medical notes would really not be relevant, I think. It's hard to imagine a scenario where my health would have anything to do with the matter in hand. Unless I have gone totally mad and started harming people, but in that case I imagine the medical and therapy notes would be very much relevant and I hope they would help me to be sectioned and get the help I would clearly need at that point.