White matter alterations and the conversion to psychosis: A combined diffusion tensor imaging and glutamate 1 H MRS study.

Introduction: Widespread white matter abnormalities and alterations in glutamate levels have been reported in patients with schizophrenia. We hypothesized that alterations in white matter integrity and glutamate levels in individuals at clinical high risk (CHR) for psychosis are associated with the subsequent development of psychosis.
Methods: Participants included 33 antipsychotic naïve CHR (Female 7/Male 26, Age 19.55 (4.14) years) and 38 healthy controls (Female 10/Male 28, Age 20.92 (3.37) years). Whole brain diffusion tensor imaging for fractional anisotropy (FA) and right frontal white matter proton magnetic resonance spectroscopy for glutamate levels were acquired. CHR participants were clinically followed for 2 years to determine conversion to psychosis.
Results: CHR participants that transitioned to psychosis (N = 7, 21%) were characterized by significantly lower FA values in the posterior thalamic radiation compared to those who did not transition and healthy controls. In the CHR group that transitioned to psychosis only, positive exploratory correlations between glutamate levels and FA values of the posterior thalamic radiation and the retrolenticular part of the internal capsule and a negative correlation between glutamate levels and the cingulum FA values were found.
Conclusion: The results of the present study highlight that alterations in white matter structure and glutamate are related with the conversion to psychosis.
Competing Interests: Declaration of competing interest Pablo León-Ortiz has served as a speaker for Shire Pharmaceuticals, Francisco Reyes-Madrigal has served as a speaker for Janssen (Johnson & Johnson) and AstraZeneca, R. Mora-Durán has served as a speaker for Schwabe Pharmaceuticals, Laura M. Rowland has served as a consultant for Otsuka America Pharmaceutical Inc., and Camilo de la Fuente-Sandoval has served as a consultant for Janssen (Johnson & Johnson). The rest of the authors report no biomedical financial interests or potential conflicts of interest.
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