I feel it would be much more beneficial to determine exactly what depression is, what causes it, and what systems are affected before time and money is spent searching for diagnoses like these. Is it a monoamine deficiency or imbalance as has been theorized since the dawn of anti-depressant medication? What about different types of depression? What makes some depression resistant to medication if it is strictly a monoamine-related disorder? So many questions still need to be addressed regarding this disease that I don't think that trying to invent new diagnoses is the best route right now.