Dysfunction of dorsolateral prefrontal cortex in antipsychotic-naïve schizophreniform psychosis

Rotman Research Institute, University of Toronto, Toronto, Ontario, Canada
Psychiatry Research (Impact Factor: 2.47). 12/2006; 148(1):23-31. DOI: 10.1016/j.pscychresns.2006.02.006
Source: PubMed


Reports of abnormal activation of the dorsolateral prefrontal cortex (dlPFC) are common in functional neuroimaging studies of schizophrenia, although very few have examined brain activity in patients close to the onset of illness. In this H(2)(15)O PET study, eight young male patients with first-episode schizophreniform psychosis and age-matched control subjects performed a version of the Stroop task that we have previously shown to engage the middle-frontal gyrus. At the time of testing, patients were antipsychotic-naïve and were scanned within 1 week of initial contact with our clinical program. All patients received a later diagnosis of schizophrenia 6 months after participating in the study. Whole-brain (within-group) and region-of-interest (between-group) analyses were carried out and data underwent spatial reproducibility testing. Compared with healthy subjects, patients showed significantly greater reaction-time (RT) interference but normal RT accuracy on the Stroop task. This pattern correlated with significant under-activation of the posterior left middle-frontal gyri in the patient versus control group. These findings support an emerging model of impaired cognitive control in schizophrenia and suggest that there is significant dysfunction of the dlPFC close to the onset of illness that may coincide with, or be modulated by, the transition-to-illness phase.

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    • "Until recently, research on cognition in drug-naïve patients with schizophrenia has been hampered by small samples and by the great variety of cognitive tests used. Several of the reports have been imaging studies usually enrolling limited samples (Cleghorn et al., 1989; Andreasen et al., 1992; Buchsbaum et al., 1992; Parellada et al., 1994; Barch et al., 2001; Salgado-Pineda et al., 2003; Jones et al., 2004; Harrison et al., 2006). Although research on drug-naïve high risk to psychosis subjects has shown cognitive impairments even before psychosis onset (Bora and Murray, 2014; Bora et al., 2014) metaanalytic evidence from drug-naïve schizophrenia subjects is lacking. "
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