Cognitive performance in psychosis has roots in childhood

By Eleanor McDermid, Senior medwireNews Reporter

The cognitive performance of patients with first-episode psychosis is not related to how long psychosis or other psychiatric symptoms have remained untreated, say researchers.

“Instead, cognitive deficits in psychosis may predate illness onset, including the prodromal phase and are likely to be part of what constitutes later susceptibility to such illness,” say study author Ashok Malla (McGill University, Montreal, Quebec, Canada) and colleagues.

The 269 patients in the study (average age 23 years) had significantly reduced performance relative to 73 mentally healthy controls on a battery of neurocognitive tests, with the largest differences seen for global cognition and verbal cognition.

The patients had a median duration of untreated psychosis of 16 weeks and a median duration of untreated illness (any signs or symptoms) of 187 weeks. But neither of these measures was associated with global or verbal cognitive performance.

Instead, scores on the Premorbid Adjustment Scale (PAS), specifically the education component, correlated with global and verbal cognition. Correlation was stronger for PAS childhood education (up to the age of 11 years) than early adolescent education (12–15 years). Late adolescent scores were not considered because of potential overlap with prodromal symptoms.

This finding “suggests that the level of cognitive functions seen at the time of presentation of [first-episode psychosis] for treatment are associated with indices that reflect the pre-symptomatic state,” say Malla et al.

Consistent with the influence of early childhood variables, socioeconomic status also significantly contributed to the variance in global and verbal cognition, and female gender contributed to variance in verbal cognition.

By contrast, factors present only in later adolescence and young adulthood, such as age at illness onset, substance use, and educational attainment, did not correlate with cognitive functioning.

PAS childhood education explained 10% and 15% of the variance in global and verbal cognition, respectively, but the researchers note that all significant variables combined explained only 15–30% of variance.

“This suggests that there are other unmeasured variables that account for a great portion of the variance in cognitive outcomes,” they write in Schizophrenia Research.

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