Cognitive, psychosocial, and behaviour gains at age 31 years from the Jamaica early childhood stimulation trial

Abstract

Background: There is little evidence on adult benefits from early childhood interventions in low and middle-income countries. We assessed adult cognition, psychosocial skills and behaviour from a stimulation trial conducted in Jamaica. Methods: Children with stunted growth (height-for age <À2SD of references) aged 9-24 months were enrolled in a two-year randomised-controlled trial of nutritional supplementation and/or stimulation. At mean age 31.79 (SD 0.40) years, 95 of 127 participants (74.8%; 53.7% male) were assessed. Children without stunted growth were also followed as a comparison group (64 of 84 participants, 76.2%). Measurements included IQ, executive function, mental health, psychosocial skills, personality traits and risk behaviours. A block permutation test, valid for small sample sizes, was used. Analyses accounted for the randomisation protocol, multiple hypothesis testing and attrition. Results: Treatment group participants (stimulation intervention with or without supplementation, n = 48) had significantly greater IQ (Hedges g effect size 0. 57; 95%CI 0.20, 0.95) and cognitive flexibility (0.61; 0.25, 0.98) compared with no-treatment (no-intervention and supplementation only, n = 47). They also had reduced depressive symptoms (0.61; 0.28, 1.00), increased grit (0.53; 0.16, 0.92) and conscientiousness (0.66; 0.31, 1.07), lower substance use (rank mean score, 0.45; 0.08, 0.81) and risk taking related to health and work (0.64; 0.27, 1.00). There were 18 significant outcomes of 33 assessed. Comparison participants had higher IQ than no-treatment (1.17; 0.81, 1.54) and treatment groups (0.62; 0.18, 1.07); and better executive function, lower social inhibition and risk taking than the no-treatment group. Conclusions: The wide-ranging benefits at 31 years from the stimulation intervention supports investment in larger scale programmes to promote early childhood development in disadvantaged children. The lower IQ in the treatment group compared with comparison participants, emphasises the need for continued efforts to prevent early childhood growth retardation.

Effect of the Jamaica Early Childhood Stimulation Intervention on Labor Market Outcomes at Age 31

“…This is a substantial increase over the treatment effect at age 22 where we observed a 25% increase in earnings (Gertler et al, 2014). Our work aligns with that of Walker et al (2021), who evaluate the effects of Jamaica Early Childhood Stimulation intervention on psychological measures at the same age we study. They find substantial and sustained benefits of the intervention on cognitive and non-cognitive skills that other studies have shown to be rewarded in the labor market (Heckman et al, 2019;Heckman and Kautz, 2012;Heckman et al, 2013).…”

“…At the end of the 2-year intervention, the developmental levels of children who received stimulation (groups 1 and 3) were significantly above those who did not (groups 2 and 4) (Grantham-McGregor et al, 1991). Significant long-term benefits were sustained through age 31 (Walker et al, 2005(Walker et al, , 2011b(Walker et al, , 2021. Moreover, stimulation treatment had positive and long-lasting impacts on psychosocial skills, and schooling attainment.…”

Gene-Environment Pathways to Cognitive Intelligence and Psychotic-Like Experiences in Children

“…Identifying underlying causal mechanisms may provide a theoretical basis for policies to support children's cognitive abilities and mental health. Given that preadolescence is the most critical period in cognitive and psychiatric development, preventive strategies to promote cognitive and psychological development in early childhood may bring substantial differences throughout life [30][31][32][33][34] . Nevertheless, previous research on early intervention discovered limited effect sizes 35,36 .…”

Editorial: Prevention is the best cure

“…This question relates to what is known as the 'prevention paradox': a preventive measure which brings much benefit at the population level, may offer relatively little benefit at the individual level (Hunt & Emslie, 2001). Two unique and strong intervention studies in this issue by Walker et al (2022) and Jantzer et al (2022) speak to the potential power of prevention, indicating that when gauging effects of prevention trials it is important to examine effects across longer time intervals and different subgroups. Jantzer et al, analyzing data of 4,873 pupils (grades 5-13) in schools implementing the Olweus Bullying Prevention Program, showed thatas expectedthe reduction in bullying leads to better mental health and quality of life.…”

“…Two unique and strong intervention studies in this issue by Walker et al. (2022) and Jantzer et al. (2022) speak to the potential power of prevention, indicating that when gauging effects of prevention trials it is important to examine effects across longer time intervals and different subgroups.…”