Dopaminergic modulation of belief-relevant cognitive processing: implications for the psychosis-spectrum

Alterations to the mesolimbic dopamine system, particularly increased pre-synaptic dopamine synthesis, have been consistently associated with psychosis and several models associate this system with delusions and hallucinations through aberrant salience, reward prediction or associative learning. However, as delusions are considered pathologies of belief, this would also suggest that this system has a role in components of normal belief formation. Through the use of pharmacological modulation, this project aims to understand the effect of alteration to the mesolimbic dopaminergic pathway on belief-related cognitive processes in the non-clinical and subclinical range to help understand the role of dopamine in the full spectrum of belief - linking the continuum of typical and pathological belief. We will test the hypothesis that i) dopamine modulation is associated with greater changes in beliefs more closely related to the psychosis spectrum, and the perceived self-relevance of beliefs in general; (ii) that these effects will be modulated by baseline schizotypy measures - indicating a role for the dopamine system in susceptibility to atypical beliefs outside the clinical spectrum.