While schizophrenia is best known for episodes of psychosis (delusions and hallucinations), it is also marked by chronic neurocognitive deficits, such as problems with memory and attention.
In a recent study led by Beth Israel Deaconess Medical Center (BIDMC), psychologists found that these neurocognitive symptoms are evident prior to the onset of psychosis.
The finding is published in JAMA Psychiatry. It suggests that these impairments may serve as early warning signs of schizophrenia.
In the study, the researchers collected neurocognitive functioning data from participants at 8 university-based, outpatient programs in the United States and Canada over the course of four years.
The study recruited 689 males and females deemed at clinical high risk (CHR) of developing psychosis and 264 male and female who were healthy.
Using 19 standard tests of visuospatial abilities, attention, language and memory, the researchers found that the high-risk group performed significantly worse than the healthy group on all 19 measures.
Among the high-risk individuals only, those who later had a psychotic disorder performed significantly worse than their high-risk peers who did not develop psychosis during the study.
Impaired working memory (cannot hold information like a phone number in mind for a short time) and declarative memory (cannot recall things learned in the last few minutes) turned out to be the key neurocognitive functions that are impaired in the high-risk group.
These findings are in line with the experiences of many people with schizophrenia who report sudden difficulties reading, concentrating or remembering things in the earliest days of the disorder.
This study is the second phase of the North American Prodrome Longitudinal Study (NAPLS), the multi-site research consortium formed in 2003 to focus on early intervention of schizophrenia.
By pooling their data, NAPLS researchers have been able to identify individuals at high risk for developing a psychotic disorder as well as the biological risk factors associated with psychosis.
This summer, the collaborators, led by researchers at Yale, published a risk calculator that can help professionals predict patients’ risk of developing psychosis.
News source: Beth Israel Deaconess Medical Center.
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