S84. THE EFFECT OF ANTIPSYCHOTICS ON GLUTAMATE LEVELS IN THE ANTERIOR CINGULATE AND CLINICAL RESPONSE MEASURED BY PANSS: A 1H-MRS STUDY IN FIRST-EPISODE PSYCHOSIS PATIENTS. (9th April 2019)

• Record Type: Journal Article
• Authors: Zahid, Uzma; Jauhar, Sameer; Pepper, Fiona; McCutcheon, Rob; Borgan, Faith; Nour, Matthew; Rogdaki, Maria; Hathway, Pamela; Murray, Robin; Howes, Oliver
• Is Part Of: Schizophrenia bulletin. Volume 45(2019)Supplement 2
• Page Start: S339
• Page End: S339
• Publication Date: 2019-04-09
• Subjects: Schizophrenia -- Periodicals; Schizophrenia -- Research -- Periodicals; 616.898005
• DOI: 10.1093/schbul/sbz020.629
• Languages: English
• ISSNs: 0586-7614

Abstract

Abstract: Background: Glutamatergic dysfunction is implicated in the pathophysiology of schizophrenia, with studies reporting elevated glutamatergic metabolites across brain regions of patients. There is consistent evidence showing a decrease in glutamate metabolites after antipsychotic administration. However, the literature on the relationship between the glutamate levels and clinical response after antipsychotics is inconsistent. In this study, we investigated whether antipsychotics change brain glutamate levels in the anterior cingulate cortex (ACC), and whether there is a relationship between baseline glutamate levels and clinical response in the ACC after taking antipsychotics, in antipsychotic naïve people or minimally treated people with first episode psychosis. We hypothesized that 1) glutamate levels decrease after antipsychotic administration; 2) glutamate levels at baseline are associated with the clinical response at follow up. Methods: The sample comprised 27 first episode psychosis patients (13 antipsychotic naïve, 7 minimally treated, and 7 were medication-free). Clinical assessment was completed for twenty-three participants at follow up, whereas follow up glutamate data was acquired for twenty patients. Proton magnetic resonance spectroscopy (MRS) was used to measure glutamate levels in the ACC at baseline and follow-up. Patient symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) at baseline and following antipsychotic treatment for a minimum of 4 weeks. Change in the clinical symptoms was measured by calculating percentage change in the PANSS score, accounting for minimum scores (7 for positive and negative symptoms). Normality of distribution was assessed using Shapiro–Wilkes test. To test the first hypothesis, we conducted a paired sample t-test. To test the second hypothesis, we used Pearson's correlation coefficients for normally distributed data and Spearman's correlation coefficients for non-normally distributed data. Results: There was no significant change found between baseline MRS signal (M = 13.72, SD = 2.14) and follow up MRS signal (M = 13.99, SD = 1.56); t(19)= -0.47, p = 0.643. No significant association was found between baseline MRS signal and PANSS positive scores (r = -0.121, n=23, p=0.584), and between baseline MRS signal and PANSS negative scores (rho = -0.182, n=23, p=0.406). Discussion: The current study observed no effect of antipsychotics on glutamate levels in the anterior cingulate cortex, and the therapeutic effects were not associated with glutamate levels acquired before antipsychotic administration. This relationship needs to be further investigated using a larger sample size. The association between changes in the glutamate levels in the anterior cingulate of first-episode psychosis patients after antipsychotic administration should be compared with a healthy population.