Is schizophrenia a neurodegenerative disorder?

Schizophrenia is a biological and behavioural disorder, which manifests itself in neurocognitive dysfunction. The question of whether this key characteristic of the disorder is related to schizophrenia being a degenerative disorder has been discussed for more than 100 years. Neuropsychological data indicate that neurocognitive functions are relatively stable over time after illness onset, whereas morphological data indicate a degenerative process. Determining whether schizophrenia is a neurodegenerative illness with progressive structural changes in the brain after debut of the illness, or a neurodevelopmental disorder starting in early life, is of significant importance for understanding the pathophysiology of the illness and its treatments. The aim of the study was to review the current literature on findings that indicate a degenerative process, as well as findings that go against a degenerative process. Several studies show that there is a decline in neurocognitive functioning prior to and in connection with onset of illness. There is no convincing evidence, however, that there is a progressive neurodegenerative process after onset of illness. We cannot provide a definite answer as to whether schizophrenia is a degenerative disorder in the sense of a progressive degeneration after illness onset. Some ideas about compensatory reactions and Cognitive Reserve Theory is outlined as possible explanations of the recent MR studies that show clear-cut structural changes in the brain after onset, at the same time as cognitive functioning does not become more impaired. If schizophrenia is degenerative, the accessibility of psychological treatments will be limited.