Impaired motor skills may indicate psychosis for kids in families with psych disorders

In children with familial high risk of schizophrenia or bipolar disorder, evidence of motor impairment skills may indicate neurodevelopmental vulnerability for psychosis.

“Motor abnormalities have clinical relevance as an underlying component of the disease process of psychotic illness and provide insights into the developmental psychopathology of psychosis,” Brigitte Klee Burton, PhD, of the child and adolescent mental health center at Copenhagen University Hospital in Denmark, and colleagues wrote in Lancet Psychiatry.

Burton and colleagues sought to assess motor development and its association with psychotic experiences in Danish children with familial high risk (FHR) of schizophrenia or bipolar disorder compared with healthy controls.

The researchers obtained data from the Danish High Risk and Resilience Study, a prospective longitudinal cohort whose baseline study was conducted between January 2013 and January 2016, with an initial follow-up conducted between March 2017 and June 2020. The cohort included 437 children (54% boys; mean age 11.99 years) born in Denmark between Sept. 1, 2004, and Aug. 31, 2009, with no, one or two parents born in Denmark with a diagnosis of either schizophrenia or bipolar disorder.

Children with no biological parent diagnosed with schizophrenia spectrum disorder or bipolar disorder were matched to those with FHR of schizophrenia (one or two parents with schizophrenia spectrum disorder) by multiple sociodemographic criteria, while those with FHR of bipolar disorder (one or two parents with bipolar disorder) were included as a non-matched group.

Motor function of participants with FHR of schizophrenia, children with FHR of bipolar disorder and children in the control group was initially evaluated at age 8 years during the baseline study, then at age 12 years during follow-up via the Movement Assessment Battery for Children — Second Edition (Movement ABC-2). Psychotic experiences were assessed by the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children — Present and Lifetime Version. The researchers utilized linear mixed model analysis to assess motor development from baseline to follow-up in each group, and logistic regression to examine relationships between definite motor problems (5th percentile on Movement ABC-2) and psychotic experiences.

Results showed that children with FHR of schizophrenia demonstrated stable developmental deficits in manual dexterity (difference in intercept –1.62 [95% CI –2.39 to –0.85]; difference in slope 0.17 [–0.48 to 0.81]) and balance (difference in intercept –1.58 [–2.34 to –0.82]; difference in slope 0.32 [–0.34 to 0.99]), and a developmental lag in aiming and catching (difference in slope –1.07 [–1.72 to –0.41]; difference in intercept –0.59 [–1.35 to 0.17]) compared with the control group. Conversely, children with FHR of bipolar disorder showed no motor developmental differences on a group basis.

Compared with the control group, data revealed that children with FHR of schizophrenia were more likely to demonstrate motor problems (OR 2.86, 95% CI; 1.60 to 5.11) as were children with FHR of bipolar disorder (OR 2.45 [1.28 to 4.70]). Researchers additionally found that children with definite motor problems across all groups were more likely (OR 1.90 [1.12 to 3.21]) to have had psychotic experiences than children without.

“Clinicians should be aware that motor impairment in childhood could reflect neurodevelopmental susceptibility to psychosis,” Burton and colleagues wrote.