Patients who are at clinical high risk for developing psychosis as well as patients with early illness schizophrenia demonstrate slow and variable motor responses, reduced engagement of right inferior frontal regions associated with inhibitory control, and decreased engagement of bilateral dorsal anterior cingulate, and these findings demonstrate these patients’ reduced ability to develop consistent and strong prepotent cognitive responses, according to study findings published in Schizophrenia Bulletin.
The study investigators performed functional magnetic resonance imaging (fMRI) during Go/NoGo task performance in clinical high-risk youth (n=30), patients with early illness schizophrenia (n=23), and healthy adolescents and young adults (n=72). During the Go/NoGo task, participants were directed to press a button in accordance with a “Go” stimuli, whereas participants were urged to withhold pressing the button in the presence of a “NoGo” stimuli. This task aimed to engage fronto-parietal regions in healthy patients to evaluate brain functioning related to response inhibition in young individuals with early illness schizophrenia and clinical high-risk patients.
Compared with the reaction times of healthy controls, the reaction times of patients with early illness schizophrenia and clinical high-risk patients were slower (P =.005) and more variable (P <.001). Investigators observed the main effects of condition for Go/NoGo activation in the bilateral fronto-parietal and subcortical brain regions (eg, premotor cortex, dorsal anterior cingular cortex (ACC), inferior and superior parietal lobules, thalamus, and striatum) (P <.001).
Relative to the Go response, participants in the early illness schizophrenia (P =.001) and clinical high risk (P <.001) groups demonstrated less NoGo response compared with healthy controls. In addition, there was less functional coupling between the dorsal anterior cingulate and medial prefrontal cortex in faster-responding healthy controls, yet this finding was not observed in early illness schizophrenia or clinical high-risk participants.
According to the investigators, the follow-up duration was too short to evaluate psychosis conversion in this patient population. Also, medication status varied among groups, further limiting the findings.
The findings from this study demonstrate “that inhibitory control alterations in schizophrenia predate psychosis onset.”
Fryer SL, Roach BJ, Ford JM, et al. Should I stay or should I go? FMRI Study of response inhibition in early illness schizophrenia and risk for psychosis [published online January 26, 2018]. Schizophr Bull. doi:10.1093/schbul/sbx198