Are persistent delusions in schizophrenia associated with aberrant salience?

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Positive psychotic symptoms in schizophrenia have been hypothesized to arise from aberrant salience.
• Previous research supported this in first-episode schizophrenia patients using the Salience Attribution Test (SAT).

Purpose of the Study:

• To investigate salience processing in patients with long-standing, treatment-refractory schizophrenia (TRS) with persistent delusions.
• To determine if aberrant motivational salience underlies persistent delusions in TRS.

Main Methods:

• Eighteen medicated TRS patients and 31 healthy volunteers completed the SAT.
• Participants performed a speeded response task involving cues with varying reinforcement probabilities across task-relevant and task-irrelevant dimensions.

Main Results:

• Both TRS patients and controls showed intact implicit adaptive salience, responding faster to high-probability cues.
• TRS patients were impaired in explicit adaptive salience, rating high-probability stimuli as less rewarding than controls.
• No significant evidence of elevated aberrant salience was found in the TRS group.

Conclusions:

• The findings do not support the aberrant salience hypothesis for persistent delusions in TRS patients.
• The study supports the notion that schizophrenia patients exhibit impaired reward learning.