New Delhi, June 10
Researchers have identified genetic factors that trigger symptoms of Attention-Deficit/Hyperactivity disorder (ADHD), autism, and anxiety.

The international study led by King’s College London, UK, examined how individuals’ varying sensitivity to environmental factors can influence levels of ADHD symptoms, autistic traits, anxiety and depression symptoms, psychotic experiences and neuroticism.

Researchers from 23 universities around the world combined data from up to 21,792 identical twins (10,896 pairs) from 11 studies to discover genetic variants linked with environmental sensitivity. This is the largest genome-wide association study (GWAS) of identical twins to date.

They identified several genetic factors that were linked with differences in environmental sensitivity within identical twin pairs. The interaction between these genetic factors and environmental exposures could explain differences in susceptibility to psychiatric and neurodevelopmental conditions, said the researchers in the paper, published in the journal Nature Human Behaviour.

“Differences in individuals’ sensitivity to life experiences can explain why the same negative or positive experiences may have varying effects on people’s mental health, depending on their genetic makeup. Our findings suggest that specific genetic variants influence how environmental exposures impact psychiatric and neurodevelopmental symptoms,” said Dr Elham Assary, Postdoctoral Researcher at King’s.

Among the genetically identical twins, the researchers found that genes linked with growth factors -- biological molecules that play important roles in neurodevelopment, immune function, and the central nervous system -- were associated with variation in autistic traits.

Genes related to reactivity to stress were linked to variation in depression symptoms. Genes involved in regulating catecholamines -- a group of hormones involved in response to stress -- were linked to variation in psychotic-like experiences, the team said.

“These findings confirm that genes influence psychiatric and neurodevelopmental traits partly through affecting how people respond to the world around them. Some people are more sensitive to their circumstances, and this can be positive in good circumstances but can make life more challenging than for others in stressful circumstances,” said Professor Thalia Eley, Professor of Developmental Behavioural Genetics at King’s.

Study finds how genetic factors influence ADHD symptoms, autistic traits, anxiety