Schizophrenia is a chronic and often severe psychotic disorder. Its causes include imbalances in mediators involved in neuroplasticity, apoptosis, cell resilience and dendritic arborization. Among these mediators, oxidative species are particularly relevant for the pathophysiology of the disease, and this is the rationale for experimental use of antioxidant medications, such as N-acetylcysteine (NAC). Onset of schizophrenia is usually preceded by a period of subtle and unspecific symptoms, the prodrome, in which preventive interventions could delay or even stop the progression to full-blown psychosis. In this article, we propose that NAC could be a useful medication to prevent evolution of schizophrenia in individuals at risk for psychosis.