ABSTRACT

Introduction The pathophysiology of schizophrenia remains incompletely understood but functional imaging techniques, such as positron emission tomography (PET), single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI) have advanced understanding of the neurobiology of the disease. An advantage of neurochemical imaging techniques such as PET and SPECT over fMRI is that they can directly quantify receptor densities, and other aspects of neurobiology, in vivo. In the past two decades neurochemical imaging has provided important data that have refined understanding of the nature of dopaminergic abnormalities in schizophrenia. The evolution of the dopamine hypothesis of schizophrenia is summarized with reference to these new data, and the latest version of the dopamine hypothesis described, together with its implications and some of the outstanding questions.