Schizophrenia is usually associated with intellectual problems. I don't think that cognitive deficits are only associated with vulnerability to schizophrenia, though there is the much citedRussell et al (1997) recently proposed that intellectual decline in  schizophrenia was a nothing more than a myth. They followed up  patients who had received an intelligence test as a child, who then  developed schizophrenia, and had their intelligence re-tested some 19  years later. There were no differences between the child and adult  IQs. However, others have criticised this study on the grounds that  the sample was unrepresentative in that the individuals had presented  to child psychiatry units and were far more intellectually impaired  than subjects in other studies of children who subsequently developed  schizophrenia.From my research prior to this question, it seems that there is a loss of ability, but likely not chronic decline over the course of the illness, one before or during the transition to psychosis. Another well known meta review claims this, that there'sno support for hypothesizing a degenerative  process in schizophrenia once positive symptoms appear... a static encephalopathy rather than a degenerative processI've seen it said that it is centered on mathematical ability.What do we know about mathematical ability pre and post psychosis, in schizophrenia? e.g., was John Nash a worse mathematician after he went mad?ReferencesRussell, A. J., et al. (1997) Schizophrenia and the myth of intellectual decline. American Journal of Psychiatry, 154(5), pp 635639.DOI: 10.1176/ajp.154.5.635 PMID: 9137118 WOS: A1997WX13000009
What do we know about schizophrenia and mathematics?
mathematical ability;schizophrenia