The Influence of Antipsychotic Treatment on Brain Reward System Reactivity in Schizophrenia Patients

Abstract INTRODUCTION:Neuroleptic dysphoria is discussed as a serious side effect of antipsychotic medication. One aspect of this condition, a reduced motivation to reach potential rewards, might be induced by a blockade of striatal D2 receptors resulting in a reduced reactivity of the brain reward system. However, since this D2 antagonistic effect is higher for typical than atypical antipsychotics, typical antipsychotics should induce a stronger dampening of brain reward system activation. This hypothesis was tested in an event related functional magnetic resonance imaging study. METHODS:A monetary reward paradigm was presented to 30 schizophrenia patients, who were treated with typical or atypical antipsychotics or a combination of both. Hemodynamic responses were analyzed during the anticipation and the reception of the reward. RESULTS:Activation of the right ventral striatum, a core region of the brain reward system, was lower in patients treated with typical antipsychotics but only during the anticipation and not the delivery of a monetary reward. DISCUSSION:This result indicates that a D2 associated reduction of brain reward system reactivity might be the neurobiological correlate of reduced motivation observed in the context of neuroleptic dysphoria. Using typical antipsychotics might worsen this effect, increasing the negative symptomatology of schizophrenia patients.