Author: Eleanor McDermid
medwireNews: Children with a high familial risk of psychosis have an increased risk of motor impairments, which are stable over time and linked to the likelihood of having psychotic experiences, research shows.
In a commentary linked to the publication in The Lancet Psychiatry, Paola Dazzan (King’s College London, UK) says that the findings are “an important contribution to the debate on whether motor problems represent trait or state markers, suggesting that they are in fact stable, which is of potential utility in the identification of susceptible individuals.”
For the study, Birgitte Klee Burton (Copenhagen University Hospital, Denmark) and co-researchers assessed 514 children from the prospective Danish High Risk and Resilience Study, including 198 with one or more biological parents diagnosed with schizophrenia spectrum psychosis, 119 who had one or more parents with bipolar disorder, and 197 children matched for age, sex and area of residence whose parents had neither condition.
These children were an average age of 7.91 years at baseline when they completed the Movement Assessment Battery for Children—Second Edition (Movement ABC-2), and a total of 437 completed a follow-up Movement ABC-2 at an average age of 11.99 years.
Children with familial risk of schizophrenia had significantly poorer manual dexterity and balance than the control group, which persisted between the two assessments, as well as a developmental lag in aiming and catching. In total, 29% versus 17% had definite motor problems (≤5th percentile) at baseline, as did 28% versus 13% at follow-up, equating to a significant 2.86-fold increased risk versus the controls.
Children born to parents with bipolar disorder did not have this persistent impairment in multiple motor domains but did have significantly poorer aiming and catching skills than controls at follow-up only, and 26% had definite motor problems, giving a significant 2.45-fold increased risk relative to the controls.
Among the children with motor impairments at follow-up, 41% of those born to parents with schizophrenia, 28% who had parents with bipolar disorder and 29% of the control group also had psychotic experiences.
“Psychotic experiences are relatively common in childhood and are mostly transitory”, write the researchers.
However, children with motor impairments were a significant 1.90-fold more likely to have experienced psychotic experiences between the two assessments than those without, independent of sex and whether they had high familial risk.
Burton and colleagues therefore suggest that “children with definite motor problems who also display psychotic experiences constitute a susceptible subgroup.”
But they say: “It remains unclear whether early motor impairment reflects biological susceptibility and, furthermore, whether motor stimulation and support can improve long-term outcomes for children at high risk.”
In his commentary, Dazzan says the findings are consistent with research showing neuromorphological differences in people with psychosis. He says that even though many of the children in the current study may never develop psychosis, the results confirm “that motor impairments represent stable traits related to psychosis susceptibility, rather than state features related to the illness or its stages.”
And he adds that the high likelihood of motor problems seen in children with high bipolar disorder risk, as well as schizophrenia risk, points to “sensorimotor problems as potential susceptibility markers for any psychosis, and not for a single diagnostic entity.”
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This independent news story was supported by an educational grant from L’Institut Servier, Suresnes, France.
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