Different hemodynamic response patterns in the prefrontal cortical sub-regions according to the clinical stages of psychosis.

Background: Symptomatic and functional outcomes in schizophrenia are associated with the duration of untreated psychosis. However, no candidate biomarkers have been adopted in clinical settings. Multichannel near-infrared spectroscopy (NIRS), which can easily and noninvasively measure hemodynamics over the prefrontal cortex, is a candidate instrument for clinical use.

Aims: We intended to explore prefrontal dysfunction among individuals at different clinical stages, including ultra-high-risk (UHR), first-episode psychosis (FEP), and chronic schizophrenia (ChSZ), compared to healthy subjects.

Method: Twenty-two UHR subjects, 27 patients with FEP, 38 patients with ChSZ, and 30 healthy subjects participated. We measured hemodynamic changes during a block-designed letter fluency task using multichannel NIRS instruments.

Results: We found that the activations of the bilateral ventrolateral prefrontal cortex, and the fronto-polar and anterior parts of the temporal cortical regions in the UHR group were lower than those of the controls, but similar to those of the FEP and ChSZ groups. However, the activations in the bilateral dorsolateral prefrontal cortex regions decrease with advancing clinical stage.

Conclusions: To the best of our knowledge, this is the first study directly comparing differences in hemodynamic changes with respect to the 3 clinical stages of psychosis. Furthermore, this study also demonstrates different patterns of impairment according to the progression of clinical stages using NIRS instruments. NIRS measurements for UHR and FEP individuals may be candidate biomarkers for the early detection of the clinical stages of psychosis.