An insight into how diagnosis is formed

A quote taken from the Wikipedia Schizoaffective page about the diagnosis's change in DSM-V.

"Citing poor interrater reliability, some psychiatrists have totally contested the concept of schizoaffective disorder as a separate entity.^[9][10] The categorical distinction between mood disorders and schizophrenia, known as the Kraepelinian dichotomy, has also been challenged by data from genetic epidemiology.^[11] Consequently, some researchers have disputed that the term "schizoaffective disorder" refers to a well defined condition, and have recommended that the term be removed from or amended in future diagnostic manuals.^[12] In April 2009, the DSM-V Psychotic Disorders Work Group headed by psychiatrist William T. Carpenter of the University of Maryland, College Park School of Medicine, reported that they will be "developing new criteria for schizoaffective disorder to improve reliability and face validity," and that they will be "determining whether the dimensional assessment of mood will justify a recommendation to drop schizoaffective disorder as a diagnostic category."^[7] Speaking at the May 2009 annual conference of the American Psychiatric Association, Carpenter said, "We had hoped to get rid of schizoaffective [disorder] as a diagnostic category because we don't think it's valid and we don't think it's reliable. On the other hand, we think it's absolutely indispensable to clinical practice."