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It’s an age-old question: is nature or nurture more responsible for how we turn out in life?

Scientists have long believed that some combination of our genes and environment – our diets, lifestyles, traumatic events, and much more – shape our personalities and health outcomes.

Now, new research indicates there’s another step involved, with our genes affecting how we respond to our life experiences – and these pathways making it more or less likely that we will grapple with a slew of psychological conditions.

The study, which was published in the journal Nature Human Behaviour, analysed data from nearly 22,000 identical twins across 11 studies, in what researchers said was the largest study yet to map the entire DNA of identical twins.

They identified genetic-environmental links to conditions as wide-ranging as anxiety, depression, psychotic experiences, neuroticism, autism, and attention deficit hyperactivity disorder (ADHD).

“These findings confirm that genes influence psychiatric and neurodevelopmental traits partly through affecting how people respond to the world around them,” Thalia Eley, one of the study’s authors and a professor of developmental behavioural genetics at King’s College London, said in a statement.

The researchers looked at identical twins because they have almost the exact same genetic code, making it possible to zero in on how people’s DNA and lived experiences interact – and what that overlap means for our well-being.

For example, if identical twins had genes that made them more sensitive to environmental factors, they were expected to be different from each other because they each had unique life experiences that set them on different paths, mental health-wise.

But if identical twins had genes that made them less sensitive to outside factors, they were expected to have more similar traits to one another.

Knowing this, the researchers identified particular genes that seemed to carry more weight than others.

Growth-related genes were associated with autistic traits, the study found, while genes related to stress reactivity were tied to depression and genes that help regulate stress hormones were tied to psychotic-like experiences.

The researchers said the findings could be used to better understand how the DNA-lifestyle nexus shapes people’s health outcomes, and what that means for people struggling with serious mental health or neurological issues.

“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,” Eley said.