Schizophrenia is a neurodevelopmental disorder that affects approximately 1% of the general population and continues to be one of the major challenges of modern medicine due to the tremendous human suffering and economic costs that it involves. Once the diagnosis of schizophrenia or a related chronic psychosis has been made, the majority of patients will only partially respond to presently available pharmacological treatments and will be afflicted by long-standing deficits affecting all aspects of mental functioning.