Emotion processing in schizophrenia and its relation to μ-opioid receptor availability

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Emotion processing deficits are a hallmark of schizophrenia, with potential links to opioid neurotransmission.
• The specific role of the mu-opioid receptor (MOR) in human emotion processing within schizophrenia remains under-investigated.
• This study investigates the association between central MOR availability and emotion processing in schizophrenia patients.

Purpose of the Study:

• To examine the relationship between central mu-opioid receptor (MOR) availability and brain activation during emotion processing tasks in schizophrenia patients.
• To compare emotion processing-related brain activation between patients with schizophrenia and healthy controls.
• To determine if MOR availability predicts neural responses within the hedonic network during emotional stimuli processing.

Main Methods:

• Nineteen schizophrenia patients and 19 healthy controls underwent functional MRI (fMRI) during emotional picture viewing and facial emotion recognition tasks.
• Positron emission tomography (PET) with [11C]-carfentanil was used to measure MOR availability (BPND).
• Group differences in brain activation and associations between MOR availability and fMRI activation were analyzed in regions of interest (ROIs).

Main Results:

• Both groups engaged the canonical cortico-limbic hedonic network during emotion processing tasks.
• No significant differences in task-related brain activation were found between schizophrenia patients and controls.
• Central MOR availability did not predict emotion-evoked brain activation in the hedonic network for either group.

Conclusions:

• Schizophrenia patients with moderate negative symptoms did not show impaired emotion-related brain activation in the hedonic network compared to controls.
• Baseline MOR availability did not influence the neural response to emotional stimuli within this network.
• These findings suggest that MOR availability may not be a primary factor in the observed emotion processing alterations in schizophrenia.