Longitudinal study of very low birth weight infants until 9 years of age; attention deficit hyperactivity and autistic features are correlated with their cognitive functions

•Some of VLBWIs at school age suffer from neuro-developmental problems.•We investigated the relationship between their cognitive functions and psychiatric symptoms.•The psychiatric profiles of VLBWIs were determined using parent report rating scales.•The index of verbal reasoning ability was inversely correlated with the scores of autism.•That of attention and working memory was also correlated with the inattentive scores in male.

BackgroundIncreasing attention has been given to neuro-developmental problems of very low birth weight infants (VLBWIs) at school age. However, it remains unknown whether their neuro-cognitive function and psychiatric symptoms are mutually associated.AimThe aim of this study was to investigate the characteristics of neuro-cognitive functions in VLBWIs and their relationship with psychiatric symptoms.MethodsA total of 160 VLBWIs who were born at our institute between 2001 and 2005 were recruited consecutively and followed up until nine years of age. The developmental profiles were obtained from 77 children (45 males and 32 females) at six to nine years of age using the ADHD Rating Scale—Fourth edition (ADHD-RS), Autism Screening Questionnaire—Japanese version (ASQ-J) and the Wechsler Intelligence Scale for Children—Third edition (WISC-III).ResultsThe full-scale intelligence quotient did not significantly differ between the male and female VLBWIs (median: 91 vs. 99, p = 0.17). The males had higher total scores (median: 13 vs. 4, p < 0.01) and higher scores on the subscales of Inattention (8 vs. 2, p < 0.01) and Hyperactivity–Impulsivity (5 vs. 1, p < 0.01) of the ADHD-RS compared with the females. The Verbal Comprehension Index (VCI) of the WISC-III was inversely correlated with the total scores of the ASQ-J for all VLBWIs (n = 77, rc: − 0.32, 95% CI: − 0.19 to − 0.01, p = 0.04). We also observed that the Freedom from Distractibility Index (FDI) of the WISC-III was significantly correlated with the Inattentive scores of the ADHD-RS (n = 45, rc: − 0.18, 95% CI: − 0.35 to − 0.02, p = 0.03) in male, but not female VLBWIs.ConclusionsWe herein report that the VCI and FDI of the WISC-III were correlated with the autism spectrum disorder and attention deficit hyperactivity disorder symptoms, respectively, in male VLBWIs.