The treatment of a problem shouldn't even depend too much on the diagnosis. I mean: it's not because two people get the same diagnosis now, that they should get the same treatment. The treatment of OCD that works for me might not work at all with another person. The psychiatrist should look at what the person says, and not so much at what the diagnosis says.
In my opinion, getting a diagnosis is close to useless. I'm not very much in favor of psychiatrists basing their entire treatment on just a diagnosis. Whether you are diagnosed correctly is completely irrelevant as long as you get the correct treatment.