How much to disclose to professionals is always a daunting thing and suicidal thoughts/self harm can really rattle some people in mental health care regardless of who they are. Personally it's been important for me to confront the issue head on ( in a manner of speaking ) but that wasn't first up. So I completely understand how starting the conversation can be very frightening, and difficult.
During that first initial few weeks/months into a year or two, it's such a fragile stage and even if you don't openly admit to feeling suicidal then most good therapists and other professionals will work it out at some stage. They may even ask directly "Are you feeling suicidal?" I also have found that different professionals have different ideas about how to deal with a patient who is actively suicidal, so when you feel the time is right to discuss it I think there needs to be some boundaries set by US, as PATIENTS.
Asking what they would do in such and such a scenario, and if you have a good support network at home and feel confident you can manage in a crisis, then ask your therapist or other professional (be it a psychiatrist, doctor, etc) for ideas to keep you safe that keep you at home because ultimately I think most of us want to remain in our home or with our family/friends. I personally feel that hospital should be a last resort. A plan is a good idea and can be a focus on therapy sessions.
Outline a plan you feel already works - it may be relaxation techniques, contacting a friend or family member you trust, distraction. What are the triggers also, can they be minimised? Have you started a new medication which is of concern?
Trust works both ways - you need to be able to trust the professional that they won't pack you off to hospital because lets face it if you disclose you are suicidal and then get sent off to hospital (and you didn't want that) then are you going to disclose it again - no way! But if you don't trust your professional then it's almost impossible to build trust and start to work through how to deal with those suicidal thoughts and/or self harm issues. Catch 22, right?
So setting the boundary has helped me. Have your own plan of what currently helps you when a crisis starts. Build on what already works and give your professional an idea of what you will accept and what you won't. "I don't want to be hospitalised, but I will message you when I notice I'm slipping in to a crisis and we will work it from there". Then dedicate some time in sessions or appointments to how well that plan works.
I have never been hospitalised and I have a list of point of contacts / priority list of what to do - I trust my direct team of treatment providers NOT to hospitalise me because we have many other options before that point. Ultimately if you are an obvious and grave risk to yourself or others, then hospital is a high possibility - but the point at which your therapist or doctor would actually do that depends on how much trust you all have in each other.
They have a duty of care to you as their patient, but it's a very personal thing how much you disclose and I'm sure most professionals understand the fear we have as patients on disclosing something that may lead to being hospitalised against our will. The more they know you, the more they will understand.
I think being honest and asking 'what if ... ?" is a good place to begin. Express your wish strongly NOT to be hospitalised and to help work with you on strategies for coping during a crisis and there are many things to work on before the need for hospitalisation. If you feel the professional isn't right for you, then seek another one.
Please take care, and stay safe.
JJ.