Is a year of therapy necessary for a solid diagnosis?

i don’t think it takes a year to get a diagnosis (when it comes to an ED), maybe a few sessions at most, so the therapist can get a feel for who you are and learn more about your ED and what it does for you? i was diagnosed AN-BP within a week of my inpatient stay but it may be different for a depersonalization disorder because depersonalization is a symptom of a handful of different disorders maybe try expressing why a diagnosis is so important to your path to feeling better and work with your therapist on figuring it out in your next few sessions