Adolescent trajectories of fine motor and coordination skills and risk for schizophrenia

Premorbid motor dysfunction is one of the earliest of developmental antecedents identified among individuals who develop schizophrenia in adulthood. However, among individuals with schizophrenia, premorbid motor dysfunction is not apparent at all stages of childhood development and may reduce with increasing age. Currently, little is known about the trajectories of motor development during adolescence among youth at-risk for the disorder. One hundred and one participants were assessed repeatedly, at approximately 24-month intervals (time 1, aged 9-12 years; time 2, 11-14 years; and time 3, 13-16 years), on the Purdue Pegboard assessment, comprising four subtests: Dominant Hand (DH), Non-Dominant Hand (NDH), Both Hands (BH), and Assembly. Fine motor and coordination skills development between ages 9-16 years was compared between youth characterised by a triad of developmental antecedents of schizophrenia (ASz, N=32); youth with at least one affected relative with schizophrenia/schizoaffective disorder (FHx; N=26); and typically developing youth without antecedents or family history (TD, N=43). Longitudinal mixed models for repeated measures indicated significant motor skills improvements with age in TD youth on the Assembly subtest only. Relative to TD youth, we found evidence for developmental deficits (i.e., dysfunction that emerged early and remained stable) among ASz youth on DH and BH subtests, and among FHx youth on the Assembly subtest. ASz youth were characterised by a developmental delay on the Assembly subtest (i.e., initial performance decrement in middle childhood that caught up with peers’ performance during adolescence). These divergences from normative motor development may reflect differences in structural and functional neural correlates.