Adolescent victimization and early-adult psychopathology: Approaching causal inference using a longitudinal twin study to rule out non-causal explanations
The Early Intervention Foundation
Tuesday, September 29, 2020
Researchers from King’s College London used data gathered from the eRisk twin study to verify the extent to which experiences of trauma occurring in childhood and adolescence predicted behavioural and mental health problems at the age of 18.
Authors: JD Schaefer, TE Moffitt, L Arseneault, A Danese, HL Fisher, R Houts, MA Sheridan, J Wertz and A Caspi
Published by: Clinical Psychological Science, 2018
Prospective study designs provide a more robust method for understanding the causal relationship between childhood events and adult outcomes than retrospective surveys, not only because adult memories tend to be faulty, but also because prospective studies clearly establish a before and after sequence of events.
Well designed prospective studies also help researchers consider the impact of the developmental timing of adverse events. For example, some studies show that trauma occurring in early childhood may be more impactful than trauma occurring during adolescence, while others show that trauma occurring in adolescence may, in fact, be more damaging.
This difference in impact can be directly tested by comparing the impact of childhood trauma to adolescence trauma through data that is collected throughout childhood.
Well designed prospective studies also allow researchers to compare the outcomes of children who are chronically exposed to trauma in comparison to those who experienced trauma only once or twice.
Study aims
Researchers from King’s College London used data gathered from the eRisk twin study to verify the extent to which experiences of trauma occurring in childhood and adolescence predicted behavioural and mental health problems at the age of 18.
The eRisk twin study involved more than 1,100 pairs of twins who were recruited at the age of five and then regularly tracked through comprehensive home assessments that took place every two to three years.
These assessments measured children’s exposure to ACEs as well as other family factors. This allowed the researchers to consider the developmental timing of this exposure, its frequency and severity. These findings were then compared to the children’s psychological functioning at the age of 18.
Key findings
The study observed a strong dose-response relationship between children’s experience of ACEs and the severity of mental health problems at the age of 18. Specifically, psychological symptoms were more severe among children who had experienced a higher number of ACE categories (for example, multiple forms of abuse and neglect) and/or more severe exposure.
The study also observed that childhood and adolescent exposure to ACEs uniquely predicted poor mental health outcomes at the age of 18.
There was also tentative evidence to suggest that ACE exposure during the adolescent years may be more impactful than exposure in earlier childhood.
Implications for practice
The authors stress that their study design was not sufficient to determine whether ACEs specifically caused negative mental health outcomes, although it clearly verified that ACEs and mental health difficulties are significantly and prospectively related.
It is important to note that the strength of this relationship remained relatively small – meaning that a childhood history of ACEs did not inevitably cause poor mental health outcomes, although it did significantly increase the risk.
- The Early Intervention Foundation is a What Works Centre that champions and supports the use of effective early intervention to improve the lives of children and young people at risk of experiencing poor outcomes
- Read more in the Adverse Childhood Experiences Special Report