Neurometabolic patterns of an "at risk for mental disorders" syndrome involve abnormalities in the thalamus and anterior midcingulate cortex

N-Acetylaspartate and Choline Metabolites in Cortical and Subcortical Regions in Clinical High Risk Relative to Healthy Control Subjects: An Exploratory 7T MRSI Study

N-acetylaspartate (NAA) and choline (Cho) are two brain metabolites implicated in several key neuronal functions. Abnormalities in these metabolites have been reported in both early course and chronic patients with schizophrenia (SCZ). It is, however, unclear whether NAA and Cho's alterations occur even before the onset of the disorder. Clinical high risk (CHR) individuals are a population uniquely enriched for psychosis and SCZ. In this exploratory study, we utilized 7-Tesla magnetic resonance spectroscopic imaging (MRSI) to examine differences in total NAA (tNAA; NAA + N-acetylaspartylglutamate [NAAG]) and major choline-containing compounds, including glycerophosphorylcholine and phosphorylcholine [tCho], over the creatine (Cre) levels between 26 CHR and 32 healthy control (HC) subjects in the subcortical and cortical regions. While no tCho/Cre differences were found between groups in any of the regions of interest (ROIs), we found that CHR had significantly reduced tNAA/Cre in the right dorsal lateral prefrontal cortex (DLPFC) compared to HC, and that the right DLPFC tNAA/Cre reduction in CHR was negatively associated with their positive symptoms scores. No tNAA/Cre differences were found between CHR and HC in other ROIs. In conclusion, reduced tNAA/Cre in CHR vs. HC may represent a putative molecular biomarker for risk of psychosis and SCZ that is associated with symptom severity.

Alterations of neurometabolism in the dorsolateral prefrontal cortex and thalamus in transition to psychosis patients change under treatment as usual - A two years follow-up 1H/31P-MR-spectroscopy study

BACKGROUND

The ultra-high risk (UHR) paradigm allows early contact with patients developing acute psychosis and the study of treatment effects on the underlying pathology.

METHODS

29 patients with first acute psychosis according to CAARMS criteria (transition patients, TP) (T0) and thereof 22 patients after two-year follow-up (mean 788 d) (T1) underwent ¹H-/³¹P-MR spectroscopy of the prefrontal (DLPFC) and anterior midcingulate (aMCC) cortices and the thalamus. N-acetylaspartate (NAA), glutamate (Glu, Glx), energy (PCr, ATP) and phospholipid metabolites (PME, PDE) were compared to 27 healthy controls by ANCOVA and correlated with patients' symptom ratings (BPRS-E, SCL-90R). For longitudinal analysis, linear mixed model (LMM) and ANCOVA for repeated measures were used.

RESULTS

DLPFC: In patients, NAA and PME were decreased bilaterally and Glu on the left side at T0. Left-sided Glu and NAA (trend) and bilateral Glx increased during follow-up. Thalamus: In TP, bilateral NAA, left-sided Glu and right-sided Glx were decreased at T0; bilateral NAA and left-sided Glx increased during follow-up. aMCC: In TP, bilateral NAA, right-sided Glu, and bilateral PME and PDE were decreased, while left-sided PCr was increased at T0. No changes were observed during follow-up.

CONCLUSION

Regardless of the long-term diagnosis, the psychotic state of illness includes disturbed neuronal function in the DLPFC, thalamus and aMCC. Treatment-as-usual (TAU), including antipsychotic/antidepressant medication and supportive psychotherapy, had an effect on the thalamo-frontal area but not or less pronounced on the neurometabolic deficits of the aMCC.