While schizophrenia is best known for episodes of psychosis – a break with reality during which an individual may experience hallucinations – it is also marked by chronic neurocognitive deficits, such as problems with memory and attention.
A multi-site cognition study led by psychologists at Beth Israel Deaconess Medical Center (BIDMC) found that these neurocognitive symptoms are evident prior to the onset of psychosis in a high-risk stage of the disorder called the prodromal phase.
The study published in JAMA Psychiatry said the findings suggest that these impairments may serve as early warning signs of schizophrenia, as well as potential targets for intervention that could mitigate the onset of the psychotic disorder and significantly improve cognitive function.
“To our knowledge, this is the largest and most definitive study of cognition in the high-risk period before onset of for psychosis/schizophrenia,” said corresponding author Larry J. Seidman, PhD, a psychologist at BIDMC and professor of psychology at Harvard Medical School.
Seidman and colleagues collected neurocognitive functioning data from participants at eight university-based, outpatient programs in the United States and Canada over the course of four years.
The observational study compared 689 males and females deemed at clinical high risk (CHR) of developing psychosis to 264 male and female healthy controls (HC). Using 19 standard tests of executive and visuospatial abilities, attention and working memory, verbal abilities and declarative memory, the researchers found that the high-risk group performed significantly worse than the control group on all 19 measures.
Among the high-risk individuals only, those who later progressed to a psychotic disorder performed significantly worse than their high-risk peers who did not develop psychosis during the study.
“Our group’s focus is on identifying early warning signs and then developing interventions to improve a person’s chances for not getting it, making it milder or delaying it,” said Seidman.