A study published in The Lancet Psychiatry found that motor impairment in childhood could be a marker for neurodevelopmental vulnerability to psychosis among children with a parent who has schizophrenia.
Investigators from Copenhagen University Hospital sourced data from the Danish High Risk and Resilience Study which recruited children born in Denmark between 2004 and 2009. In this analysis, the children who had 1 or both parents with schizophrenia (n=198) or bipolar disorder (BD; n=119) were matched with children without familial high risk (FHR) for psychosis (n=197). All children were evaluated for signs of psychosis, and risk for psychosis was related with motor function assessed at ages 8 and 12 years.
The children with FHR for schizophrenia or BD and controls had mean ages of 7.91, 7.94, and 7.88 years at baseline; 54%, 53%, and 54% were boys; 89%, 88%, and 88% were right-handed; the Children’s Global Assessment Scale (GDAS) functioning scores were 67.97, 73.55, and 77.71 points (P <.0001); and estimated intellectual quotient (IQ) scores were 102.19, 104.13, and 105.01 (P =.024), respectively.
Compared with controls, the children with FHR for schizophrenia had significantly poorer manual dexterity (least squares mean difference [LSMD], -1.33; P =.0001), aiming and catching (LSMD, -1.54; P <.0001), and balance (LSMD, -1.14; P =.0005) skills at follow-up. The children with FHR for BD only had significantly poorer aiming and catching motor skills compared with controls (LSMD, -1.15; P =.0025). Among the 2 cohorts with FHR for psychosis, no significant differences were observed.
At baseline and follow-up, the children in the FHR cohorts were more likely to have definite motor problems (25%-29% vs 13%-17%) compared with controls, respectively. Among the children who had definite motor problems, the children with FHR for schizophrenia were more likely to also have psychotic experiences at baseline (58%) and follow-up (41%) compared with controls at baseline (24%) and follow-up (29%). For the cohort with FHR for BD, the subset with definite motor problems were more likely to also have psychosis at baseline (41%) but not at follow-up (28%).
Together, these data indicated that children with definite motor problems at follow-up were at an increased risk for psychotic experiences since baseline than those without motor problems (odds ratio [OR], 1.90; P =.017). This relationship was attenuated when adjusting for gender (adjusted OR [aOR], 0.83; P =.43) and FHR for BD (aOR, 0.93; P =.81) but remained significant for FHR for schizophrenia (aOR, 1.68; P =.048).
The major limitation of this study was the short follow-up duration. Additional study is needed to evaluate long-term outcomes.
Study authors concluded, “Our results indicate that motor development through childhood on a group level is impaired in children with FHR of schizophrenia, and not impaired in children with FHR of bipolar disorder, compared with controls. These findings are consistent with the neurodevelopmental model for schizophrenia, in which neurodevelopmental disturbances, such as motor impairments, are present in childhood.”
Burton BK, Krantz MF, Skovgaard LT, et al. Impaired motor development in children with familial high risk of schizophrenia or bipolar disorder and the association with psychotic experiences: a 4-year Danish observational follow-up study. Lancet Psychiatry. 2023;10(2):108-118. doi:10.1016/S2215-0366(22)00402-3