In a recent paper by Ujval S. Pathak, Aydan Mehralizade, Terry E. Goldberg and Anthony W. Zoghbi examine the relationship between schizophrenia and dementia. People with schizophrenia are four- to 20-fold more likely to develop dementia than the general population. Up to 70% people with the disorder may develop dementia by age 80. Schizophrenia is a chronic psychiatric disorder that affects how a person thinks, feels and behaves. It is often characterised by symptoms such as hallucinations (e.g. seeing or hearing things that are not there), delusions (i.e. false beliefs), disorganised thinking and long-term difficulties with memory, attention and decision-making.
With their study, the authors explored the topic using retrospective cohort study of 155 people with severe, extremely treatment-resistant schizophrenia. The researchers compared cognitive, clinical and genetic data with large datasets of people with Alzheimer disease, frontotemporal dementia, Lewy body dementia, vascular dementia, as well as healthy controls.
The results showed, nearly all participants (98.7%) had cognitive impairment consistent with at least mild dementia and almost half (47.1%) met criteria for severe dementia, with an average MoCA score of 9.8. Importantly, the pattern of cognitive impairment differed from that seen in Alzheimer disease and other common dementias but closely resembled, and appeared to intensify, the cognitive profile previously observed in schizophrenia. Genetic analyses also did not support common dementia causes, as participants lacked typical dementia-related mutations and had a lower frequency of known Alzheimer risk genes such as APOE4. Furthermore, the evidence suggests that the observed cognitive decline could not be explained by factors such as medications, cardiovascular risk or institutionalisation.
In conclusion, the findings support the longstanding idea that dementia seen in severe schizophrenia represents a distinct clinical syndrome related to the disorder itself rather than being caused by coexisting neurodegenerative diseases or external factors. The authors are hopeful that their findings contribute to reducing misdiagnoses and inappropriate treatment. Further research exploring cognitive decline and dementia in schizophrenia to identify reliable biological signals, is needed, and identifying people with the highest risk for this decline and intervening before the onset of psychosis should be a research priority.
Find the full article here: https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2847069?utm_source=researchgate.net&utm_medium=article
