Abstract
Cognitive impairment is an important predictor of disability in schizophrenia. Dopamine neurotransmission in cortical brain regions has been suggested to be of importance for higher-order cognitive processes. The aim of this study was to examine the relationship between extrastriatal dopamine D2-R availability and cognitive function, using positron emission tomography and the high-affinity D2-R radioligand [11C]FLB 457, in an antipsychotic-naive sample of 18 first-episode psychosis patients and 16 control subjects. We observed no significant associations between D2-R binding in the dorsolateral prefrontal cortex or hippocampus (β = 0.013–0.074, partial r = −0.037–0.273, p = 0.131–0.841). Instead, using Bayesian statistics, we found moderate support for the null hypothesis of no relationship (BFH0:H1 = 3.3–8.2). Theoretically, our findings may suggest a lack of detrimental effects of D2-R antagonist drugs on cognition in schizophrenia patients, in line with clinical observations.
Highlights
Diagnostic criteria for schizophrenia include positive symptoms and negative symptoms.Beyond these symptoms, a majority of patients have a cognitive impairment, with global functioning significantly below that of healthy controls (HCs)[1]
positron emission tomography (PET) studies have shown a slight increase of this receptor subtype in schizophrenia in striatum[8], and in parallel striatal D2 receptor (D2-R) has in several studies been reported to be associated with measures of processing speed and executive function in healthy subjects[12,13,14] as well as in drug-free patients with schizophrenia[15]
The purpose of this study was to examine the relationship between D2 receptor availability and cognitive function in an antipsychotic drug-naive sample of first-episode psychosis (FEP) patients and HC subjects
Summary
Diagnostic criteria for schizophrenia include positive symptoms (delusions, hallucinations, disorganized speech, and behavior) and negative symptoms (loss of motivation, blunted affect, etc.). Beyond these symptoms, a majority of patients have a cognitive impairment, with global functioning significantly below that of healthy controls (HCs)[1]. PET studies have shown a slight increase of this receptor subtype in schizophrenia in striatum[8], and in parallel striatal D2-R has in several studies been reported to be associated with measures of processing speed and executive function in healthy subjects[12,13,14] as well as in drug-free patients with schizophrenia[15]
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