In a large population study, researchers found that children experiencing psychotic symptoms lagged behind their typically developing peers of the same age in neurocognition.
Moreover, this lag was found to be present as early as age 8 when children of that age experienced psychotic symptoms.
The senior researcher was Rachel Gur, M.D., Ph.D., a professor of psychiatry at the University of Pennsylvania. The results were reported on February 5 in JAMA Psychiatry.
The study included 2,321 youth aged 8 to 21 who reported having psychotic symptoms. They were compared with 1,963 typically developing children with no psychiatric disorders and also with 981 children with psychiatric symptoms other than psychosis.
Each of the subjects was given, for one hour, a battery of neurocognitive tests to evaluate different types of neurocognitive performance—for example, executive function, episodic memory, complex cognition, social cognition, and sensorimotor speed. The results from the psychosis group were compared with those of the typically developing and other psychiatric symptom groups.
The researchers found that subjects with psychotic symptoms lagged behind typically developing subjects of the same age. Furthermore, psychotic-symptom subjects with more severe symptoms showed greater developmental lag than those with milder symptoms. The delay associated with psychotic symptoms occurred across all neurocognitive domains, ranged between six and 18 months, and was present already as early as at age 8 in those children who experienced psychotic symptoms at that age.
As for the subjects with nonpsychotic psychiatric symptoms, they did not show a neurocognitive delay, indicating that the delay was limited to psychosis.
The results have clinical implications, the researchers said. “Combined clinical and neurocognitive assessment can facilitate early detection and targeted intervention to delay or ameliorate disease progression.” For instance, “Although as a group psychotic-symptom individuals show greater lag in complex cognition than other domains, including executive function, the lag pattern may differ for individuals and can form the basis for designing tailored intervention approaches.”
Gur and her team now plan to follow up to 300 of the psychotic-symptom subjects and 200 of the typically developing subjects. It will thus “become possible to test whether early indicators, such as neurocognitive dysfunction, predict and deteriorate in association with onset of full psychosis among those with subthreshold symptoms at baseline,” Tyrone Cannon, Ph.D., of Yale University wrote in an accompanying editorial.
The research was funded by the National Institutes of Health. ■