By age two, the average child in high-income countries has received roughly three courses of antibiotics — most often a beta-lactam such as penicillin, amoxicillin, or cephalosporin — for ear infections, respiratory illnesses, or post-surgical prophylaxis. The clinical benefits of these prescriptions are well established. What is less widely appreciated …
Among infants in the Canadian Healthy Infant Longitudinal Development (CHILD) study, the bacterial composition of the gut at 12 months of age predicted cognitive, language, and motor performance at age 2. Babies whose late-infancy microbiomes were dominated by Bacteroides scored roughly 4–5 points higher on Bayley-III subscales than those with …
Children born extremely preterm — at less than 28 weeks of gestation — start school with measurable cognitive disadvantages relative to term-born peers. A meta-analysis of post-1990 cohorts found a roughly 12-point full-scale IQ gap, with similar deficits in working memory and executive function (Twilhaar et al., 2018). Against this …
About 10% of newborns are classified as small for gestational age (SGA), defined as birth weight below the 10th percentile for gestational week. Most SGA newborns recover normal growth in the first two years. Their cognitive trajectory, by contrast, does not converge with their term-born peers: across longitudinal cohorts, SGA …
The Eves et al. (2021) individual participant data (IPD) meta-analysis published in JAMA Pediatrics answers a question that single cohorts have not been able to answer cleanly: do the cognitive deficits associated with very preterm (VPT, <32 weeks) or very low birth weight (VLBW) birth persist into full adult cognitive …
The Mancini et al. (2021) paper in Translational Psychiatry reports a retrospective observation that may—if independently replicated—reframe early pharmacological intervention in a population at extreme genetic risk for schizophrenia. In children and adolescents with 22q11.2 deletion syndrome (22q11.2DS), long-term treatment with selective serotonin reuptake inhibitors (SSRIs) was associated with attenuated …
The Moutoussis et al. (2021) Neuron paper proposes that variation in decision-making ability is itself a measurable individual-difference dimension—called decision acuity—that is partially distinct from general intelligence and that carries its own associations with psychopathology and brain connectivity. The claim is operationalized through a substantial multi-task battery and resting-state fMRI …
The standard practice in psychometric test publication is to develop norm tables by stratifying the standardization sample into age bands and computing percentile-rank tables within each band. The procedure is intuitive and has been the de facto industry standard for the better part of a century, but it has known …
The Roozenbeek, Maertens, McClanahan, and van der Linden (2020) paper in Educational and Psychological Measurement is a methodologically focused stress-test of the gamified misinformation-inoculation paradigm developed in the same group’s earlier 2019 Palgrave Communications work. Where the 2019 paper established that the Bad News game produces measurable improvement in players’ …
Heavy or dependent cannabis use during adolescence is associated with a small but measurable decline in IQ — about 2 points on average, concentrated in verbal ability. The effect is real, but it is not the dramatic 8-point loss often quoted from a single 2012 study. Twin studies and confounder-adjusted …
