My opinion is not to share with- school, for exactly the reasons you mentioned. Too much can be taken out of context, especially by folks who are not mental health professionals. Also, in my son's case, his psychiatric records contained info about some sexualized behaviors he engaged in at an Residential Treatment Center (RTC) - not a chance I wanted that documentation to become part of his school record.
My policy for years has been if the school wants medical information, they have to ask me for it (I don't even authorize the SD to contact my pcs' pediatrician) I would then ask the appropriate professional for the info, and after I've reviewed it, I would forward it on to school. Interestingly, since I've adopted this practice, the school has not needed any information on either of my special needs kids.
Since the school has requested "medical records", in the spirit of cooperation I would ask specifically what they want - diagnoses, medication lists, test results, what? Tell them you'll be happy to request the information from psychiatrist/therapist for them - be sure you review it before you give the SD anything.