during adolescence can enhance the long-term benefits of interventions
delivered in the first 1,000 days of a child’s life, writes Prof Mark
Tomlinson from the Department of Psychology in an article published recently by
Children living in conditions of adversity are at considerable risk of poor physical and emotional health, violence, educational failure, and more broadly of not meeting their developmental potential.
The past half-century has seen an exponential increase in our understanding of how experiences in the very early years of life are foundational for brain development. The concept of the “first 1000 days" (from conception to the end of the second year) describes the time of life when the brain develops most rapidly, and where caregiver stimulation and affection “sculpt" the brain, forming experience-dependant neuronal connections.
The first 1,000 days narrative has been an advocacy godsend, instrumental in shaping and garnering support for many global initiatives in early child development.
We now know a lot about how to deliver interventions that improve mother-infant interaction and infant attachment, enhance child cognitive development and contribute to improved peer relationships — in ways that are highly cost effective. There is also some compelling evidence of the long-term benefits of interventions delivered in the first 1,000 days, such as improved wage earnings in adulthood.
However, these findings, coupled with the success of the first 1,000 days narrative, risk leading to assumptions that early intervention is not just necessary, but also sufficient to ensure lifetime benefits.
No silver bullet
The evidence, however, is not as unequivocal as some have argued. Much of it comes from studies with small sample sizes. Studies conducted in the US may not apply to contexts characterised by extreme poverty and persistent adversity over the life-course.
And recent research has shown how brain development continues into adolescence and even early adulthood. In contexts of chronic adversity, early gains may subsequently fade out — a phenomenon there is growing evidence for. In these contexts, it is unlikely early interventions will be sufficient to significantly improve developmental trajectories across an entire life. Top-up interventions during adolescence may be key.
What we don't know currently is how to ensure that early gains can be built upon and reinforced to ensure they do not fade out over time. We also know little about how early gains might be able to be bolstered by later interventions, providing additive benefits that a single intervention (whether early or late) might not be able to achieve.
When intervening with children living in multi-risk environments, top-up interventions at critical points in life may be necessary to maintain or enhance initial gains and to resurrect lost benefits. An example might be a school-based group problem-solving intervention to prevent adolescent mental disorders; it could build on an intervention in the first thousand days aimed at improving early mother-child attachment.
Our team from the Institute for Child and Adolescent Health Research at Stellenbosch University in South Africa are currently evaluating, using a randomised control trial, the effect of one such second-wave intervention, targeting a cohort of adolescents who had participated as infants, along with their mothers, in a home-based early intervention delivered by community health workers.
In the initial first 1000 days intervention, community health workers were trained to visit pregnant women and then the mother and her child across the first six months of the infant's life. The intervention aimed to improve mother-infant interaction, focusing on key aspects like sensitivity, non-intrusiveness, engagement and turn-taking.
In the additive adolescent intervention, we are focussing on building problem-solving skills and peer relationships to reduce interpersonal violence and promote adolescent mental health.
Beyond these desired outcomes, we are also examining a range of questions around what is needed to optimise child and adolescent development across the life-course.
- For those mothers and adolescents whose early benefits have faded out, does receiving the adolescent intervention resurrect the early benefits?
- Where benefits have persisted, does receiving the adolescent intervention provide a further boost?
- Could only receiving the adolescent intervention (for teens who did not receive an intervention as infants) provide unique benefits?
This study could answer important questions about how waves of interventions at critical developmental phases may be of greater benefit than single one-off interventions.
Policy makers and governments caught in the “early intervention is sufficient" narrative may be inadvertently missing later opportunities to build on early gains, resurrect early benefits that may have faded out and, even more importantly, to potentially enhance the benefits of early stand-alone single interventions. —Mark Tomlinson