Should diagnosis and classification be kept separate in psychiatry?

In medicine it is common practice to diagnose patients before classifying their symptoms. In psychiatry, however, the two procedures cannot be kept separate; they overlap and are interlinked. To discuss relevant classification systems and the relationship between diagnosis and classification and to find out what kind of relationship is the best one for psychiatry. The literature was searched and a conceptual analysis was performed on the basis of relevant literature, manuals and principles formulated by psychiatrists. It is argued that deliberation, an important part of the diagnostic process, can only play a significant role if diagnosis and symptom classification are kept completely separate. In this process of deliberation there should be a role for clinical phenomena such as improvement of symptoms, worsening of symptoms, objectification and reification, and psychiatrists should have the opportunity to consider whether these aspects really belong to the field of psychiatry. In psychiatry the relationship between diagnosis and symptom classification is not clear-cut. However, since deliberation plays a major role in psychiatric diagnosis, it is important that psychiatrists continue to keep diagnosis separate from symptom classification. Unlike other medical specialists, psychiatrists sometimes classify an illness before making a diagnosis. Existing guidelines and an all-embracing guideline regarding diagnosis need to be harmonised. Confusion and misdiagnosis could be reduced if classifications from two classification systems were to be included in medico-psychiatric diagnosis.