A low second-to-fourth digit ratio (2D:4D) is a purported biomarker of increased intrauterine androgenic exposure, presumably linked to postnatal behavior. We aimed to examine the associations between 2D:4D and adolescence behavior problems expected from high (externalizing and attention problems) or low (internalizing problems) prenatal androgen exposure. We conducted a cross-sectional study of 1042 Colombian schoolchildren aged 11–18 y. We examined whether caliper-assessed 2D:4D was associated with behavior problems per the Youth Self-Report questionnaire. Mean problem standardized score point differences were estimated between hand- and sex-specific quintiles of 2D:4D with use of multivariable linear regression. Lower right-hand 2D:4D was associated with decreased externalizing and internalizing behavior problem scores. Corresponding lowest-to-median quintile adjusted mean differences (95% CI) were −4.6 (−7.5, −1.7) and −3.5 (−6.4, −0.6) points in boys; and −3.4 (−5.9, −0.9) and −3.5 (−6.2, −0.8) points in girls. Lower right-hand 2D:4D was also related to less attention and thought problems in boys, and to less social problems among girls. Associations were nonlinear, apparent only below 2D:4D medians, and stronger with the right than the left hand. In conclusion, right-hand 2D:4D is related to behavior problems in adolescence in directions that are not fully consistent with an androgenic exposure origin.

Little effort has been made to integrate developmental cascades with maternal/paternal parenting in a single investigation. The present study seeks to test cascading effects among academic and internalizing/externalizing symptoms and their associations with maternal/paternal parenting across three time points from 8 to 10 years. Data for this investigation came from a nationally representative prospective cohort study of children born in April through July of 2008 in South Korea who were followed up annually. The sample included 1,598 families (48.5% girls). Parents rated their parenting and teachers rated children’s internalizing/externalizing problems and academic performance. Structural equation modeling showed that externalizing problems were negatively related to academic performance. Academic performance was negatively related to internalizing problems and positively related to maternal/paternal authoritative parenting, which in turn led to children’s higher academic performance. Bidirectional relations were found between academic performance and externalizing problems and between paternal authoritative parenting and children’s internalizing problems. Findings suggested cascading effects and their associations with parenting were not attributable to child gender, intelligence, or socioeconomic differences. These findings lend support to adjustment erosion and academic incompetence models and underscore the need for greater attention to the role that fathering may play in children’s development and mothering.

We examined the associations of middle childhood and adolescence nighttime sleep duration with adolescence internalizing and externalizing behavior problems per the Youth Self-Report (YSR) and the Child Behavior Checklist (CBCL) questionnaires, in a cohort of 889 Colombian schoolchildren. We estimated adjusted differences with 95% confidence intervals (CI) in mean behavior problem t-scores in standardized units between recommended sleep duration categories and as a continuous exposure using multiple linear regression and restricted cubic spline models, respectively. Compared with sleep duration within recommendations, middle childhood sleep above recommendations was related to 4.6 (95% CI: 1.6, 7.6; p = .004) and 5.4 (95% CI: 1.2, 9.7; p = .01) adjusted units higher YSR and CBCL externalizing problem scores, respectively. In continuous exposure analyses, this association seemed restricted to children aged ≥11 years. Longer sleep, both in categories and as a continuous exposure, was also associated with increased CBCL internalizing problems. Results did not differ by sex or weekend/weekday sleep. Sleeping under recommendations in middle childhood was not significantly related to behavior problems; nevertheless, shorter sleep in adolescence, in both categorical and continuous scales, was significantly related to behavior problems. In conclusion, behavior problems in adolescence are associated with longer sleep in middle childhood and shorter sleep in adolescence.

We examined the associations of middle childhood infectious morbidity and inflammatory biomarkers with adolescent internalizing and externalizing behavior problems. We recruited 1018 Colombian schoolchildren aged 5–12 years into a cohort. We quantified white blood cell (WBC) counts and C-reactive protein at enrollment and prospectively recorded incidence of gastrointestinal, respiratory, and fever-associated morbidity during the first follow-up year. After a median 6 years, we assessed adolescent internalizing and externalizing behavior problems using child behavior checklist (CBCL) and youth self-report (YSR) questionnaires. Behavior problem scores were compared over biomarker and morbidity categories using mean differences and 95% confidence intervals (CI) from multivariable linear regression. Compared with children without symptoms, CBCL internalizing problem scores were an adjusted 2.5 (95% CI: 0.1, 4.9; p = .04) and 3.1 (95% CI: 1.1, 5.2; p = .003) units higher among children with moderate diarrhea with vomiting and high cough with fever rates, respectively. High cough with fever and high fever rates were associated with increased CBCL somatic complaints and anxious/depressed scores, respectively. WBC >10,000/mm3 was associated with both internalizing problem and YSR withdrawn/depressed scores. There were no associations with externalizing behavior problems. Whether or not decreasing the burden of common infections results in improved neurobehavioral outcomes warrants further investigation.

There is a need to understand how the joint development of externalizing and internalizing behaviors is related to substance use, particularly among historically understudied and often disadvantaged populations. Latent class models were used to estimate patterns of externalizing behaviors and internalizing behaviors in the form of depressive and anxious symptoms from age 6 to 14 among 390 Black and Hispanic youth. Then, growth curve models of substance use between the ages of 15 and 19 were estimated as a function of joint latent class membership. Only elevated levels of externalizing behaviors were associated with higher levels of substance use through age 18. Internalizing behaviors appeared to serve as a protective factor among those with moderate displays of externalizing behavior only. Additionally, growth in substance use from ages 15 to 19 was slower among those who displayed the highest level of externalizing behaviors, and internalizing behaviors appeared to moderate growth (and serve as protective factor) among those who displayed moderate levels of externalizing behaviors. The findings underscore the importance of pattern profiles based on observations of the joint development of problem behaviors to assess risk for substance use, particularly in understudied populations where risk/protective factors may operate in a unique manner.