Neurocognitive Deficits Documented in Children at High Risk of Schizophrenia
By Marilynn Larkin
NEW YORK—Seven-year-old children at familial high risk (FHR) of schizophrenia have "widespread neurocognitive impairments" and should be monitored to prevent transition to psychosis, researchers say.
Dr. Nicoline Hemager of Mental Health Services, Capital Region of Denmark, Kildegaardsvej and colleagues studied 514 seven-year-olds (46% girls), including 197 children with FHR schizophrenia, 118 with FHR bipolar disorder, and 199 matched controls.
Children were assessed using the Child Behavior Checklist (CBCL), Children's Global Assessment Scale (CGAS), and various neurocognitive function tests.
As reported online June 20 in JAMA Psychiatry, compared with the control group, the FHR schizophrenia group exhibited significantly more problem behavior (mean CBCL score 27.2 vs. 17.0) and significantly lower functioning (mean CGAS score, 68.1 vs. 77.7).
In the FHR bipolar group, the problem behavior score (mean, 23.4) and functional score (mean, 73.6) were in between the scores of the other study groups, and differed significantly from the control group on both scores and from the FHR schizophrenia group on the CGAS score.
Children with FHR schizophrenia were significantly impaired compared with controls on processing speed and working memory, executive and visuospatial functions, and declarative memory and attention. Further, they performed significantly worse on these tests than the FHR bipolar disorder group.
In contrast, there were no differences between FHR bipolar children and controls on these functions.
"The absence of neurocognitive deficits in children with FHR (bipolar disorder) suggests distinct neurodevelopmental manifestations in these FHR groups at this age," the authors state. "Early detection of children with FHR (schizophrenia) and cognitive impairments is warranted."
Dr. Terry Goldberg, Professor, Medical Psychology in Psychiatry and Anesthesiology at Columbia University Medical Center in New York City, called the study "strong," with a large number of subjects and an extensive neuropsychological battery of tests.
"There are some caveats," he told Reuters Health by email. "It is unclear how well the control group is matched to the other groups in terms of socioeconomic status."
"It is also unclear how many of the children already have DSM-diagnosable disorders (e.g., ADHD, conduct disorder, mood disorder, 'prodromal' schizophrenia) and if they are the ones driving the cognitive findings," he noted. "Certainly the high-risk groups have more elevated behavioral rating scores."
"In terms of implications," he added, "these children are at increased risk for learning disorders, social role function, and later, vocational problems."
Dr. Carol Lieberman, a psychiatrist and schizophrenia expert in private practice in Beverly Hills, California and former assistant clinical professor of psychiatry at UCLA's Neuropsychiatric Institute, commented, "Although it is difficult to disagree with the results of the specific neurocognitive tests that the study administered, there are flaws with the premises and implications."
"For example," she told Reuters Health, "this study measures neurocognition in seven-year-olds with a familial predisposition to schizophrenia or bipolar illness, but they did not take into consideration the familial environment these children grew up in."
"How many episodes of psychosis did their parents experience during the children's lifetime? What were the nature of these psychotic episodes? The investigators jump to the conclusion that neurocognitive functions are endophenotypes of schizophrenia," she said by email, "without taking into consideration any impact of the effect of growing up with one or both parents who have had episodes of schizophrenic or bipolar psychosis themselves."
"The investigators seem to imply that giving children these neurocognitive tests at age seven would help to identify those who are more likely to go on to develop schizophrenia," she noted.
"But there could be many explanations for deficits on neurocognitive tests at this age," Dr. Lieberman said, "and to label them early on as destined to develop (full-blown) schizophrenia, could do more harm than good."
Lead and principal authors Dr. Hemager and Dr. Jepsen did not respond to requests for a comment.
JAMA Psychiatry 2018.
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