Hi. I’m a Consultant Psychiatrist. A few thoughts:
Don’t worry about what the Professor is a specialist in...a Professor is someone who is both a Consultant Psychiatrist and has a special research interest/expertise. They tend to be very good diagnosticians, as they will spend a lot of their clinical time doing new assessments (a long interview to reach a diagnosis) as second opinions for other consultants. They will do these for the whole range of mental health problems. Schizophrenia/psychosis may simply be their research interest and not indicative of the range of their clinical work.
It is helpful to see people on their own first, then with someone else. BUT it is now really hard as a doctor and psychiatrist to ask people to allow this. Leaves us open to complaints, criticisms and accusations. I think you will get the best assessment you can by going in alone, but you are (likely) going to have to be the one to ask your cousin to wait in the waiting room.
When you are in assessment you’ll be asked a LOT of questions. I would recommend going with the flow. Try to wait till they say they have no more questions, and ask if there’s anything you want to add, to bring other stuff up. Many people don’t realise we have a route plan in our heads, they we have spent years training to use. We start using it instinctively and deductively to reach a diagnosis and plan, so please allow the psychiatrist to do this. It is a question and answer session rather than counselling or therapy, and understanding this and going with this is what will take you to the clearest diagnosis and treatment plan. Psychiatrists are just a type of doctor, but we have our hands tied behind our backs a bit by a lack of blood tests etc that other doctors rely on -instead we ask LOADS of questions to get all the info we need. Even when you are saying “no” “never” “nothing like that” this is useful, and not a waste of time as some people seem to feel.
This is going to sound harsh, but just to be completely honest and up front...don’t get hung up on how you’ll talk about your sexual assault. Psychiatrists aren’t (usually) therapists, or counsellors. We’re not psychologists either. We make medical diagnoses and gather info for that. So yes, we want to know about the things that may have shaped your personality, traumas etc but in a “I was assaulted by a stranger/my relative/my teacher in 1999, it happened once/many times over x years” kind of way. A long detailed discussion is not necessary -it is not likely to help you (or the psychiatrist use their time sensibly to reach a diagnosis). I say this because often people will feel they have talked about these things in great detail only to realise at the end that they won’t see that doctor again, or they’ll have to go through that all over again with the person who is actually going to offer the therapy.
If you have tried lots of medications, make a list before hand and jot down your thoughts about how useful or not you found them, including side effects.
Similarity, if you have had lots of mental health input, write every encounter you can remember down -dates, who you saw, what treatment.
Try not to blow this encounter up in your mind. It’s a Q&A on you, and you are an expert in you. There are no wrong answers. And it shouldn’t be too emotionally invasive, as it isn’t therapy, it’s an assessment.
Hope that helps a bit.