Personality disorder in DSM-5: an oral history.

As the revision process leading to DSM-5 began, the domain of personality disorder embodied the highest aspirations for major change. After an initial prototype-based proposal failed to gain acceptance, the Personality and Personality Disorders Work Group (P&PDWG) developed a hybrid model containing categorical and dimensional components. A clash of perspectives both within the P&PDWG and between the P&PDWG and DSM-5 oversight committees led to the rejection of this proposal from the main body of DSM-5. Major issues included conflicting ways of conceptualizing validation, differences of opinion from personality disorder experts outside the P&PDWG, divergent concepts of the magnitude of evidence needed to support substantial changes, and the disagreements about clinical utility of the hybrid model. Despite these setbacks, the 'Alternative DSM-5 Model of Personality Disorder' is presented in Section III of the DSM-5. Further research should clarify its performance relative to the DSM-IV criteria reprinted in the main DSM-5 text.

What kinds of things are psychiatric disorders?

This essay explores four answers to the question 'What kinds of things are psychiatric disorders?' Essentialist kinds are classes whose members share an essence from which their defining features arise. Although elegant and appropriate for some physical (e.g. atomic elements) and medical (e.g. Mendelian disorders) phenomena, this model is inappropriate for psychiatric disorders, which are multi-factorial and 'fuzzy'. Socially constructed kinds are classes whose members are defined by the cultural context in which they arise. This model excludes the importance of shared physiological mechanisms by which the same disorder could be identified across different cultures. Advocates of practical kinds put off metaphysical questions about 'reality' and focus on defining classes that are useful. Practical kinds models for psychiatric disorders, implicit in the DSM nosologies, do not require that diagnoses be grounded in shared causal processes. If psychiatry seeks to tie disorders to etiology and underlying mechanisms, a model first proposed for biological species, mechanistic property cluster (MPC) kinds, can provide a useful framework. MPC kinds are defined not in terms of essences but in terms of complex, mutually reinforcing networks of causal mechanisms. We argue that psychiatric disorders are objectively grounded features of the causal structure of the mind/brain. MPC kinds are fuzzy sets defined by mechanisms at multiple levels that act and interact to produce the key features of the kind. Like species, psychiatric disorders are populations with central paradigmatic and more marginal members. The MPC view is the best current answer to 'What kinds of things are psychiatric disorders?'

Physical factors negatively affecting evaluation of long-term biodegradation experiments of polychlorinated biphenyls.

Behaviour of PCB added in the form of a technical mixture (Delor 106) and [14C]PCB 77 into different aqueous model cultivation media in long-term experiments was studied. The work was focused on monitoring PCB recovery from liquid media in the absence of micro-organisms. GC-ECD and radioanalysis were utilised for determination of PCB in the examined systems. Strong relations between duration of experiments, composition of media, degree of chlorination of biphenyls, and recovery of PCB were found. The lowest yields of PCB were observed for the extracts from model solutions based on N-limited cultivation media without veratryl alcohol and Tween 80. The addition of these components, mainly of Tween 80, caused a significant increase of PCB recoveries.