DSM stands for Diagnostic and Statistical Manual of Mental Disorders.
They explained in an email to Psychology Today's Allen Frances, M.D.:
"As we see it, there are two major problems with the proposal. First, the proposed classification is unnecessarily complex, incoherent, and inconsistent. The obvious complexity and incoherence seriously interfere with clinical utility. Although the proposal is touted as an innovative and integrative hybrid system, this claim is spurious. In fact, it consists of the juxtaposition of two distinct classifications (typal and dimensional) based on incompatible models without any attempt to reconcile or integrate them into a coherent structure. This structure also creates confusion since it is not clear whether the clinician should use one or both systems in routine clinical practice.
Second, the proposal displays a truly stunning disregard for evidence. Important aspects of the proposal lack any reasonable evidential support of reliability and validity. For example, there is little evidence to justify which disorders to retain and which to eliminate. Even more concerning is the fact that a major component of proposal is inconsistent with extensive evidence. The latter point is especially troublesome because it was noted in publication from the Work Group that the evidence did not support the use of typal constructs of the kind recommended by the current proposal. This creates the untenable situation of the Work Group advancing a taxonomic model that it has acknowledged in a published article to be inconsistent with the evidence."
As it stands now, says Frances, who was chair of the DSM-IV Task Force, "the DSM 5 personality section is not readable, much less usable. It will be ignored by clinicians and will do grave harm to research."
Two Who Resigned From DSM-5 Explain Why by Allen Frances, M.D., Psychology Today