Blunted ventral striatal reactivity to social reward is associated with more severe motivation and pleasure deficits in psychosis

TL;DR

Reduced brain activity in response to social rewards is linked to worse motivation and pleasure issues in people with psychosis.

Contribution

This study shows that social reward processing in the ventral striatum is uniquely linked to motivation and pleasure deficits in psychosis.

Findings

Ventral striatum reactivity to social incentives is associated with clinician-rated motivation and pleasure deficits in psychosis.

This association remains significant after controlling for other symptoms and monetary reward reactivity.

Diminished striatal activation during social reward receipt may underlie social impairments in psychosis.

Abstract

Among individuals living with psychotic disorders, social impairment is common, debilitating, and challenging to treat. While the roots of this impairment are undoubtedly complex, converging lines of evidence suggest that social motivation and pleasure (MAP) deficits play a key role. Yet most neuroimaging studies have focused on monetary rewards, precluding decisive inferences. Here we leveraged parallel social and monetary incentive delay fMRI paradigms to test whether blunted reactivity to social incentives in the ventral striatum–a key component of the distributed neural circuit mediating appetitive motivation and hedonic pleasure–is associated with more severe MAP symptoms in a transdiagnostic sample enriched for psychosis. To maximize ecological validity and translational relevance, we capitalized on naturalistic audiovisual clips of an established social partner expressing positive feedback. Although both paradigms robustly engaged the ventral striatum, only reactivity to social incentives was associated with clinician-rated MAP deficits. This association remained significant when controlling for other symptoms, binary diagnostic status, or ventral striatum reactivity to monetary incentives. Follow-up analyses suggested that this association predominantly reflects diminished striatal activation during the receipt of social reward. These observations provide a neurobiologically grounded framework for conceptualizing the social-anhedonia symptoms and social impairments that characterize many individuals living with psychotic disorders and underscore the need to establish targeted intervention strategies.

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