Shared information is re-encrypted for (exclusive) access by new trusted parties. This could be specialist practitioners or a different GP. Up to you. Tell your doctors what (only) they need to know.
Being able to keep the information shared with your Shrink seperate to the records shared with your GP is one example. Less fibs. Required. Everywhere. This helps doctors do (their) medicine. Once.
Patients know their records with various doctors are private. Less (necessary) lies and better medicine.