Neurodevelopment or neurodegeneration: Review of theories of schizophrenia

Abstract

Many hypothesis have tried to explain the aetiology of schizophrenia, the abnormal neurodevelopmental hypothesis is one of the most widely acknowledged and is based on the presence of both prenatal and perinatal disorders, differences in IQ or the existence of genetic abnormalities, which, with the interaction of certain environmental factors, schizophrenia could occur at some point in the development. This hypothesis provides a good account of how these factors result in an alteration in the normal development and how they can lead to a disorder of schizophrenia. On the other hand, a smaller but not insignificant number of studies based on variables such as the presence of neurotoxicity in the brains of individuals with schizophrenia, alterations at the structural and brain connectivity, suggest the existence of a degenerative process in the course of this disease. In this work, we review the different factors underlying both hypotheses, some of which are difficult to categorize in either approach given the controversy and lack of consensus in their interpretation of the available data. Finally, we discuss the need for a non-exclusive alternative model to help understand the available evidence on the origin, course and consequences of the disease.