Children who carry a particularly high number of genetic variants associated with ADHD also have a statistically greater risk of experiencing severe neglect and childhood maltreatment.

This is shown in a new study recently published in the scientific journal JAMA Psychiatry.

Researchers from the Department of Biomedicine at Aarhus University have examined how individuals' genetic profiles relate to their risk of being subjected to childhood maltreatment - across five major psychiatric diagnoses such as ADHD and schizophrenia.

The results show that genetics is a risk factor. This is according to Ditte Demontis, professor of psychiatric genetics at the Department of Biomedicine and one of the researchers behind the study.

"One of the most striking findings is that children with a high genetic risk for ADHD are more often subjected to childhood maltreatment across all the psychiatric diagnoses we examined. When we looked specifically at children with ADHD, we found that among those with the highest genetic risk for ADHD, 5.6% were subjected to maltreatment. In comparison, only 3.3% of children with ADHD in the low genetic risk group experienced maltreatment," she says.

In the study, childhood maltreatment is defined as exposure to physical, sexual, or emotional abuse and/or deprivation or severe neglect during childhood. The study builds on existing knowledge and clarifies that our genetics is a risk factor.

Environment and genetics interact

The risk of childhood maltreatment is also influenced by whether the child grows up with parents who themselves have a psychiatric diagnosis.

The study found that the risk of childhood maltreatment was 5.7% in the high genetic risk group if the child’s parents had a psychiatric diagnosis. By comparison, the risk was 2.5% in the same genetic high-risk group if the parents did not have a diagnosis.

“We can conclude that the combination of a child's genetics - which may predispose them to externalizing behavior - and a psychiatric diagnosis in the parents are factors that increase the risk of childhood maltreatment,” explains Ditte Demontis.

The child is never to blame

The study also shows that girls are generally more exposed to childhood maltreatment than boys - but this is not genetically determined.

"This suggests that there are societal or social factors that result in girls being more often affected by childhood maltreatment," the researcher says.

She emphasizes that neglect is never the child’s fault.

“A child’s genetics is never the cause. And the study does not show that children with ‘risk genetics’ will necessarily be maltreated. But statistically, it increases the risk, and by understanding the relevance of both genetic and environmental risk factors, we as a society might be able to intervene earlier and offer support,” she says.

Relevant for researchers and practitioners

This is the first time that researchers - with such a large dataset and genetic precision - have shown how genetics and known risk factors, such as parental mental illness, contribute to a particularly high risk of childhood maltreatment and neglect.

"The study shows correlations, but we do not yet know specifically how ADHD genetics increases the risk," says Ditte Demontis.

The findings are especially relevant for researchers and professionals in psychiatry and genetics who work to understand the interaction between genes and environment.

“What’s new and more complex is that this study shows how genetic factors can increase the risk of being exposed to childhood maltreatment, and that ADHD genetics in particular increases the risk across all the psychiatric diagnoses studied. In doing so, the study builds on existing knowledge and adds a genetic layer to our understanding,” says Ditte Demontis.

Behind the research

• The study is basic research. The researchers used polygenic scores - a measure of how many genetic variants in a person's genome are associated with a given psychiatric diagnosis or trait - to examine genetic differences between groups.
• Collaborators: Helen Minis, School of Health and Wellbeing, University of Glasgow, and Edmund Sonuga-Barke, Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology & Neuroscience, King’s College London
• External funding: Lundbeck Foundation, Novo Nordisk Foundation
• Read more in the scientific article: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2833167

Contact

Professor Ditte Demontis
Aarhus University, Department of Biomedicine
Phone: +45 28 53 97 46
Email: ditte@biomed.au.dk 

This text is based on machine translation