F80. THE NEUROBIOLOGY OF NEGATIVE SYMPTOMS: PET AND MR IMAGING FINDINGS IN FIRST EPISODE AND CHRONIC SCHIZOPHRENIA

Autor: Oliver D. Howes, Sameer Jauhar, Tiago Reis Marques, Fiona Pepper, Abhishekh Ashok
Rok vydání: 2019
Předmět:
Zdroj: Schizophrenia Bulletin. 45:S284-S284
ISSN: 1745-1701
0586-7614
DOI: 10.1093/schbul/sbz018.492
Popis: BACKGROUND: Negative symptoms are common in schizophrenia, evident from first episode, and associated with poor functional outcome. There is no currently licensed treatment for negative symptoms, indicating the need to better understand the mechanisms underlying them. However, the neural mechanisms underlying negative symptoms in patients are unclear. It has been hypothesized that impairments in cortical function could contribute to the development of negative symptoms. However, the neural mechanism linking these has not been tested. Thus, in study 1 we aimed to test this using fMRI imaging in first episode antipsychotic free patients. It has also been hypothesized that avolition-apathy and anhedonia, core negative symptoms, involves the dysfunction of the striatal reward system. Pre-clinical evidence suggests that opioid neurotransmission in the striatum is linked to hedonic responses. However, mu-opioid availability in-vivo and its relation to reward function in schizophrenia has not been studied. Thus, in study 2 we investigated mu-opioid availability and reward processing in schizophrenia using PET and fMRI imaging. METHODS: Study 1: 59 volunteers (29 antipsychotic naïve/ free patients with first episode psychosis (FEP) and 30 healthy control volunteers) were included in the fMRI study. Participants were studied using functional magnetic resonance imaging whilst performing the n-back working memory task. Blood oxygen level-dependent (BOLD) response and the Positive and Negative Syndrome Scale (PANSS) were measured. Study 2: 40 volunteers (20 patients with schizophrenia and 20 matched volunteers) participated in a PET and fMRI study using PET imaging with a mu-opioid specific ligand [11C]-carfentanil and fMRI imaging using a monetary incentive delay reward task. Patients with schizophrenia were required to have at least moderate severity negative symptoms. RESULTS: In study 1 there was significantly greater activation in healthy controls (HC) compared to patients (FEP) when participants performed the 2-back task compared to the 1-back condition in the thalamus (p = 0.010) and hippocampus (p = 0.007) but were no significant correlations between BOLD response and the PANSS negative symptom scores. In study 2, there was significantly lower mu-opioid receptor availability in the striatum of patients with schizophrenia (patients vs controls (mean ± SD): 1.54 ± 0.26 vs 1.7 ± 0.22, Cohen’s d= 0.7, p
Databáze: OpenAIRE
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