Physical diseases are diagnosed based off blood tests, various types of scans, etc. The criteria are agreed upon and will be diagnosed the same by any doctor based off test results. Psychiatric diseases are diagnosed based off observable behavior or reports of the patients thoughts. The research is yet to find a reliable biomarker for diagnosing any psychiatric illness, quite unlike psychical illnesses. Different psychiatrists might diagnose the same behavior as different disorders. In the sense that you "do" your behavior, this is accurate.