I'm in the USA as well, and like puzzclar, I've never been strip searched when being hospitalized. They do, however, bring me scrubs or a gown and ask me to remove all of my clothes and put on what they've given me. In once instance (out of more than 10) I do remember a hospital staff member having to be present as I changed, but she just faced the door (not me) and grabbed my clothes as I lay them on the bed and put them into a belongings bag.

As was suggested by puzzclar, please do not let this stop you from asking for help if you need it. You've come to trust your T enough to talk about your suicidal ideation, so would it be possible to trust him enough to explain that you cannot handle a strip search if inpatient treatment is recommended?