Background: Despite evidences of breastfeeding for preventing acute physical illnesses in infants, the evidence for the association between breastfeeding and long-term cognitive development is not yet convincing.Methods: The data of nationwide representative sample of 1752 children born between 2008 and 2009 in Korea were prospectively assessed from the fetal period to examine the benefits of breastfeeding and cognitive development. Breastfeeding duration was prospectively assessed by parents. The Korean Ages and Stages Questionnaire and the Korean version of Denver II were used to assess early development annually from 5.5 to 26.2 months of age. Language development at 3 years of age was assessed with Receptive and Expressive Vocabulary Tests. Cognitive function at 8 years of age was assessed using multifactorial intelligence test.Results: In the analysis of categorical variables, children who were breastfed for > 1 and ≤ 3 months displayed significantly higher odds ratios for delayed development assessed with Korean Ages and Stages Questionnaire at 14.1 months than those breastfed for > 3 and ≤ 6 months (OR = 2.21; 95% CI: 1.08, 4.50), but no significant differences in other rounds of assessments. In the analysis with continuous variables, there were significant differences among six groups of breastfeeding duration in communication (F = 3.72;p < 0.002) and problem solving (F = 3.09;p < 0.009) at 14.1 months, expressive language (F = 3.74;p = 0.002) at 3 years, and calculation (F = 2.43;p < 0.033) at 8 years. When analyzed by two groups, children breastfed for > 3 months scored significantly higher on the communication (F = 17.71;p < 0.001) and problem-solving (F = 11.26;p < 0.001) subscales at 14.1 months, and expressive language (F = 12.85;p < 0.001) at 3 years, and vocabulary (F = 6.78;p = 0.009) and language inference (F = 5.62;p = 0.018) at 8 years, compared to children breastfed for 3 months or less.Conclusion: We found that cognitive development was improved in children that were breastfed for > 3 months. Although these results are supported by previous studies, it is important to note that other factors were reported as larger determinants of cognitive development than breastfeeding. Future studies that examine the underlying mechanism for the association between breastfeeding and cognitive development are warranted.

Ji Won Lee, Bong-Jo Kim, Cheol-Soon Lee, Boseok Cha, So-Jin Lee, Dongyun Lee, Jiyeong Seo, Young-Ji Lee, Youn-Jung Lee, Eunji Lim, and Jae-Won Choi. J Korean Acad Child Adolesc Psychiatry 2021;32:161-9. https://doi.org/10.5765/jkacap.210024

Objective: The purpose of this study was to evaluate the positive impact of mobile neurofeedback (MNF) in neurotypical children compared to sham mobile neurofeedback. Methods: Neurotypical children aged 10– 15 participated in the study. All subjects were assessed using the Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version Korean Version (K-SADS-PL-K) and confirmed to have no psychiatric symptoms. The participants were randomly assigned to the MNF active (N=31) or sham control (N=30) groups. The MNF program was administered using a mobile app for 30 min/day, 3 days/week, for 3 months. All participants and their parents completed self-report scales and participants complete neurocognitive function assessments including the continuous performance test, Stroop, children’s color trails test-1 and 2, and intelligence test at baseline and after the 3-month MNF program. Results: This study involved 61 participants (mean [SD] age, 11.24 [1.84] years; 30 male participants [49.2%]). To verify the difference between the MNF group and the sham group, 2(MNF-Sham) X 2(Pre-Post) repeated measures ANOVA was performed. The main effect of the K-scale (Korea Internet addiction scale) between-group factor (MNF vs Sham) was not significant, but the main effect of the within-group factor (Pre vs Post) was significant (F=7.595, p=0.008). The interaction effect of between-group factors and within-group factors was also significant (F=5.979, p=0.017). In other self-reported scales of children and parents and neurocognitive function assessments, there was no significant difference between the two groups. Conclusion: Active mobile neurofeedback significantly improved children’s K-scale score compared to the sham group. Therefore, mobile neurofeedback could be an easy-to-access therapeutic option for children at risk of Internet addiction. On the other hand, there was no significant difference in other scales and neurocognitive function. A 3-month intervention may not have been long enough to cause change, so longer interventions are needed for confirmation.

Background: Lead is known to be associated with attention-deficit/hyperactivity disorder (ADHD) even at low concentrations. We aimed to evaluate neurocognitive functions associated with lead in the blood and the interactions between lead and dopaminergic or noradrenergic pathway-related genotypes in youths with ADHD. Methods: A total of 259 youths with ADHD and 96 healthy controls (aged 5–18 years) enrolled in this study. The Korean Kiddie Schedule for Affective Disorders and Schizophrenia–Present and Lifetime version was conducted for psychiatric diagnostic evaluation. Blood lead levels were measured, and their interaction with dopaminergic or noradrenergic genotypes for ADHD; namely, the dopamine transporter (DAT1), dopamine receptor D4 (DRD4), and alpha-2A-adrenergic receptor (ADRA2A) genotypes were investigated. All participants were assessed using the ADHD Rating Scale-IV (ADHD-RS). Participants also completed the continuous performance test (CPT) and Stroop Color-Word Test (SCWT). Analysis of covariance was used for comparison of blood lead levels between ADHD and control groups. A multivariable linear regression model was used to evaluate the associations of blood lead levels with the results of ADHD-RS, CPT, and SCWT; adjusted for intelligence quotient (IQ), age, and sex. A path analysis model was used to identify the mediating effects of neurocognitive functions on the effects of blood lead on ADHD symptoms. To evaluate the effect of the interaction between blood lead and genes on neuropsychological functions, hierarchical regression analyses were performed. Results: There was a significant difference in blood lead levels between the ADHD and control groups (1.4 ± 0.5 vs. 1.3 ± 0.5 μg/dL, p = .005). Blood lead levels showed a positive correlation with scores on omission errors(r = .158, p = .003) and response time variability (r = .136, p = .010) of CPT. In the multivariable linear regression model, blood lead levels were associated with omission errors (B = 3.748, p = .045). Regarding the effects of lead on ADHD symptoms, hyperactivity-impulsivity was mediated by omission errors. An interaction effect was detected between ADRA2A DraI genotype and lead levels on omission errors (B = 5.066, p = .041). Conclusions: Our results indicate that neurocognitive functions at least partly mediate the association between blood lead levels and ADHD symptoms, and that neurocognitive functions are affected by the interaction between blood lead levels and noradrenergic genotype.