Do eating disorders constitute breaking a doctor-patient confidentiality?

i know it can be broken if you might cause harm to yourself or others but im not sure about eating disorders?

Yes they can because they are considered dangerous to the patient. They can disqualify you from receiving organ transplants in the same way that doing drugs does.

It depends on your age I think. If you are younger then 18 your doctor may be able to tell your parents or guardian.

it depends on the severity - you have to be pretty sick before they will risk bringing in outside non-medical help by which time everyone around you knows anyway.
ALSO i find it very frustrating when people ask questions of a semi-legal nature and don't state where they live - different countries have different rules!