From: mjs23x@gmail.com   
      
   A Nose for Schizophrenia Risk   
      
   Date: 10/08/2015   
      
   A Nose for Schizophrenia Risk   
   Vidya Kamath adjusts electrodes on a research assistant’s head in   
   preparation for measuring cortical responses in the brain as the subject   
   describes an odor. Sniffin Sticks, foreground, are also used.   
      
   Of all the sensory systems, olfaction is most closely linked to the frontal   
   and temporal brain regions implicated in schizophrenia. Measuring potential   
   olfactory dysfunction may therefore provide a window into schizophrenia   
   pathology.   
      
   And the earlier in life these symptoms are identified, the better, says Johns   
   Hopkins neuropsychologist Vidya Kamath—ideally, before a patient’s first   
   psychotic episode.     
      
   Kamath recently published findings about the relative specificity of olfactory   
   deficits in individuals with schizophrenia, healthy family members and young   
   people at clinical or genetic risk for psychosis but who have not yet been   
   diagnosed with a    
   specific disorder. Clinical risk subjects are those individuals without a   
   first- or second-degree relative with schizophrenia who are experiencing   
   attenuated symptoms of psychosis. Genetic risk subjects have a first-degree   
   relative (parent or sibling)    
   with a diagnosis of schizophrenia and may be experiencing early symptoms.   
      
   To Kamath’s knowledge, this is the first study to show that youth at   
   clinical risk are impaired on both odor identification and odor    
   iscrimination, similar to observations of adult schizophrenia patients.   
      
   These findings are important, says Kamath, because they may represent a   
   genetic marker not only of vulnerability for schizophrenia, but possibly of a   
   neurodevelopmental biomarker associated with the actual development of   
   psychosis.   
      
   Kamath’s work draws on insights from her research on the First Episode   
   Psychosis Project, a five-year study focused on the longitudinal changes that   
   occur over the early course of psychosis. Led by Johns Hopkins Schizophrenia   
   Center Director Akira Sawa,   
    the study examines how aberrant brain changes in late-adolescence contribute   
   to the onset and early progression of schizophrenia.    
      
   Typically, Kamath and her team see two research participants a week. A   
   thorough olfactory evaluation includes measures of odor identification,   
   detection threshold, discrimination and judging the pleasantness or   
   unpleasantness of an odor.   
      
   In this most recent study, using Sniffin’ Sticks odor identification and   
   discrimination tests, Kamath and her colleagues found that patients and   
   relatives were impaired on odor identification, but odor discrimination   
   impairment was limited to the    
   patient group. In these patients, olfactory impairment was correlated with   
   negative symptoms, such as flat affect.   
      
   A similar pattern emerged in at-risk youth: Genetic-risk youth were impaired   
   on odor identification, while clinical at-risk youth were impaired on both   
   tasks.   
      
   “When you’re looking for biomarkers,” says Kamath, “you want measures   
   that differentiate between those who will develop schizophrenia and those who   
   are unlikely to develop the illness. Olfactory dysfunction may be an early   
   warning sign of disease    
   vulnerability. Our goal is to come up with a predictive measure.”   
      
   That requires rounds of exhaustive tests, Kamath says. Participants are asked   
   to smell an odor and name it. Then she and her team chart the minimum   
   concentration at which they can identify different scents. Finally,   
   participants are asked to rate the    
   pleasantness and intensity of pleasant and unpleasant odors. Other   
   investigators perform a biopsy using a small skin sample from the nasal area   
   to correlate cellular and molecular changes with behavioral olfactory measures.   
      
   Many of these at-risk youths, notes Kamath, are also grappling with negative   
   symptoms, such as apathy and social withdrawal. But the ability to predict   
   schizophrenia onset earlier in its course—through nasal clues—can open the   
   door to further    
   interventions, sooner rather than later. These include social and community   
   support and low doses of medication to lessen the severity of symptoms.   
      
   The next step, says Kamath, is to look at electrophysiological responses to   
   odors to examine whether at-risk youth display neurophysiological impairments   
   in early olfactory sensory processing.   
      
   Meanwhile, with each suspicious finding in patients at risk for schizophrenia,   
   says Kamath, “the most important question we can ask is, how do we help   
   those who have the illness improve their quality of life?”   
      
      
   http://www.hopkinsmedicine.org/news/articles/a-nose-for-schizophrenia-risk   
      
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