What a diagnosis can do is allow you to have a clear frame of reference for what you are going through. It can allow you to find an understanding of your symptoms in the framework of a particular diagnosis rather than living in that limbo-land of not really knowing what the heck is going on. Being able to put a name on what I was experiencing, being able to do a bit of research and reading that was directed for people living with what I was dealing with every day was hugely helpful. I could read and see that what was happening was "normal" for that diagnosis. It was definable rather than feeling like I was trying to understand whisps of elusive smoke all the time. I have never felt like my diagnosis "defined me", but my diagnosis DOES help me understand me and accept me a great deal better than living all the time with not knowing for sure what the heck was going on.