Daily-life stress differentially impacts ventral striatal dopaminergic modulation of reward processing in first-degree relatives of individuals with psychosis

Abstract

Emerging evidence shows that stress can impair the ability to learn from and pursue rewards, which in turn has been linked to motivational impairments characteristic of the psychotic disorder. Ventral striatal dopaminergic neurotransmission has been found to modulate reward processing, and appears to be disrupted by exposure to stress. We investigated the hypothesis that stress experienced in the everyday life has a blunting effect on reward-induced dopamine release in the ventral striatum of 16 individuals at a familial risk for psychosis compared to 16 matched control subjects. Six days of ecological momentary assessments quantified the amount of daily-life stress prior to [¹⁸F]fallypride PET imaging while performing a probabilistic reinforcement learning task. Relative to the controls, individuals at a familial risk for psychosis who encountered more daily-life stress showed significantly diminished extent of reward-induced dopamine release in the right ventral striatum, as well as poorer performance on the reward task. These findings provide the first neuromolecular evidence for stress-related deregulation of reward processing in familial predisposition to psychosis. The implication of daily-life stress in compromised modulation of reward function may facilitate the design of targeted neuropharmacological and ecological interventions.

Keywords: Dopamine; First-degree relatives; Psychosis; Reward; Stress; VST.