However, these “joints,” the boundaries between psychiatric disorders, such as that between bipolar disorder and schizophrenia, are far from clear. Prior versions of DSM followed the path outlined by Emil Kraeplin in separating these disorders into distinct categories. Yet, we now know that symptoms of bipolar disorder may be seen in patients with schizophrenia and the reverse is true, as well.
Further, our certainty about the boundary of these disorders is undermined by growing evidence that both schizophrenia and bipolar disorder emerge, in part, from the cumulative impact of a large number of risk genes, each of which conveys a relatively small component of the vulnerability to these disorders. And since many versions of these genes appear to contribute vulnerability to both disorders, the study of common gene variations has raised the possibility that there may be diagnostic, prognostic, and therapeutic meaning embedded in the high degree of variability in the clinical presentations of patients with each disorder.
In addition, many symptoms of schizophrenia and bipolar disorder are traits that are present in the healthy population but are more exaggerated in patient populations. To borrow from Einstein, who struggled to reconcile the wave and particle features of light, our psychiatric diagnoses behave like waves (i.e., spectra of clinical presentations) and particles (traditional categorical diagnoses). Although new genetic approaches may revise our current thinking, such as studies of microdeletions, microinsertions, and microtranslocations of the genome, the wave/particle approach to psychiatric diagnosis places a premium on understanding the “real” clustering of patients into subtypes as opposed to groups created to correspond to the current DSM-IV.
Latent class analysis is one statistical approach for estimating the clustering of subjects into groups. In their study of 270 Irish families, published in the July 15th issue of Biological Psychiatry, Fanous and colleagues conducted this type of analysis, with subjects clustered into the following groups: bipolar, schizoaffective, mania, schizomania, deficit syndrome, and core schizophrenia. When they divided the affected individuals in the study using this approach, they found four regions of the chromosome that were linked to the risk for these syndromes that were not implicated when subjects were categorized according to DSM-IV diagnoses.
Dr. Fanous notes that this finding “suggests that schizophrenia as we currently define it may in fact represent more than one genetic subtype, or disease process.” According to John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System: “Their findings advance the hypothesis that the variability in the clinical presentation of patients diagnosed using DSM-IV categories is meaningful, providing information that may be useful as DSM-V is prepared. However, we do not yet know whether the categories generated by this latent class analysis will generalize to other populations.” This paper highlights an important aspect of the complexity of establishing valid psychiatric diagnoses using a framework adopted from traditional categorical models.
Jayne Dawkins | alfa
Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
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Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
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Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
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On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
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