To hold stringently, however, to the view that schizophrenia is either a neurodevelopmental disorder or a neurodegenerative disease is short-sighted. Development does not end at birth, but instead continues throughout the lifespan and involves critical periods of development, particularly in the periadolescent period, with the timing of disease sometimes linked to genetics, such as with Huntington’s disease, which may not manifest itself until later

in life. Feinberg32 appreciated the notion that development is not static and that it occurs across the lifespan. He observed that development may proceed Inhibitors,research,lifescience,medical normally up to adolescence, which he viewed as a critical time period when faulty programming leads to abnormalities in synaptic pruning in those adolescents who go on to develop schizophrenia. Mednick and McNeil33

also Inhibitors,research,lifescience,medical had a broad view of neurodevelopment, and of the progression of illness. They described a “two-hit” model of schizophrenia, Inhibitors,research,lifescience,medical where genetics, and/or possible assaults during neurodevelopment, comprised the “first hit.” They believed, however, that schizophrenia did not develop without a “second hit,” which occurs later in development, around the time of adolescence or early adulthood. Thus a broad view of neurodevelopment, Inhibitors,research,lifescience,medical which includes the possibility of disease progression, has been proposed in the past and needs to be more appreciated today when we evaluate the role of brain abnormalities in schizophrenia. More recent MRI findings, reviewed below, suggest that changes in the brain are observable at or even before the first onset of psychosis, with post-onset changes observed in a relatively short time period following Inhibitors,research,lifescience,medical illness onset. Progressive changes, however, in and of themselves, do not provide evidence that schizophrenia is a neurodegenerative disorder. More recent MRI Fossariinae findings have,

nonetheless, rekindled an interest in neurodegenerative theories of schizophrenia, although it is clear that early motor abnormalities, neurological soft signs prior to illness onset, sulco-gyral pattern abnormalities and cavum septum pellucidum abnormalities commonly exhibited by patients with schizophrenia point to the important role of learn more neurodevelopment in schizophrenia (see review in Shenton et al3). There is also no evidence for a loss of neurons and no gliosis in postmortem studies of schizophrenia.34 These findings, taken together, suggest that schizophrenia is not a neurodegenerative disorder, at least not as defined by conventional criteria.