19 Nov Auditory Perceptual Abnormalities As High Risk Indictor of Progression to Psychosis
MedicalResearch.com Interview with:
Guillermo Horga, MD, PhD
Assistant Professor of Clinical Psychiatry
Columbia University Medical Center
MedicalResearch.com: What is the background for this study?
Response: Some people who eventually develop schizophrenia or other psychotic disorders have early “prodromal” symptoms such as subtle perceptual abnormalities and unusual thoughts that precede the onset of these disorders by months or even years. These subtle symptoms are typically not fully formed or met with full conviction, which distinguishes them from full-blown symptoms of psychosis.
The “prodromal” phase has been the subject of intense study as researchers believe it can provide an invaluable window into the neurobiological processes that cause psychotic disorders as well as an opportunity to develop early preventive interventions. Persons who experience “prodromal” symptoms (known as “clinical high-risk” individuals) tend to report a variety of relatively subtle perceptual abnormalities (e.g., heightened sensitivity to sounds, distortions in how objects are perceived, momentarily hearing voices of speakers who are not present), unusual thoughts, and disorganized speech, some of which have been shown to be particularly informative in distinguishing who among these persons will eventually develop a full-blown psychotic disorder, a prediction that is clinically important as it may indicate the need for close monitoring of individuals who are at the greatest risk. Even though subtle perceptual abnormalities are common in this population, the available research indicates that they are as a whole uninformative for clinical prediction purposes. However, previous research in this area had never examined in detail whether assessing perceptual abnormalities in different sensory domains (such as visual versus auditory abnormalities) separately could be more informative than assessing them as a whole.
MedicalResearch.com: What are the main findings?
Response: Our study at Columbia University Medical Center assessed these abnormalities separately in a group of “clinical high-risk” individuals who were followed up for up to two years.
To our surprise, only when we assessed visual and auditory abnormalities separately did we realize that they provided opposite clinical information, with the former indicating lower risk and the latter indicating higher risk of developing a psychotic disorder. Even more surprising was the finding that in our study visual abnormalities were more clinically informative than any other clinical assessments, including other well-established clinical predictors of the development of psychotic disorders.
MedicalResearch.com: What should readers take away from your report?
Response: Our study suggests that not all perceptual abnormalities may mean the same thing clinically.
While perceptual abnormalities in the visual domain seem to indicate that “clinical high-risk” individuals are less likely to develop a psychotic disorder, the opposite may be true for those in the auditory domain. This dissociation also suggests that the neurobiological mechanisms underlying abnormalities in these two domains may differ. In conjunction with the fact that visual abnormalities are substantially less common than auditory abnormalities in full-blown psychotic disorders but not in “clinical high-risk” states, these findings point to the possibility that “prodromal” individuals with visual abnormalities may go on to develop other, non-psychotic disorders (or continue experiencing subtle, subclinical phenomena) and thus explain the gap between visual and auditory symptoms observed in full-blown psychotic disorders. More generally, our results suggest that it may not be a good idea to automatically assume that a theoretical relationship between symptoms necessarily implies that these symptoms have the same clinical and neurobiological meaning.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: While these findings are preliminary and need to be replicated in independent studies, our findings suggest that future studies into the neurobiological basis of psychosis (and of psychiatric disorders more broadly) should evaluate different symptom domains separately and test their relationships empirically.
They also suggest that studying auditory symptoms of psychosis, and their neurobiological differences compared to visual symptoms, may be a fruitful venue to enhance our understanding of this puzzling condition.
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Lehembre-Shiah E, Leong W, Brucato G, Abi-Dargham A, Lieberman JA, Horga G, Girgis RR. Distinct Relationships Between Visual and Auditory Perceptual Abnormalities and Conversion to Psychosis in a Clinical High-Risk Population. JAMA Psychiatry. Published online November 16, 2016. doi:10.1001/jamapsychiatry.2016.3055
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