The Genetics of Risk

DNA may determine your taste for danger.

Psychiatry professor Abraham Palmer, PhD ’99, considers himself a bit of a risk-taker. When he was younger, he enjoyed zipping around on a motorcycle. More recently, it’s a bicycle. But he still tends to drive over the speed limit.

Some risk-taking can be life-threatening, yes, but it’s not all bad, he says.

Abraham Palmer, PhD ’99, psychiatry professor, vice chair for basic research at UC San Diego School of Medicine.

“Being willing to take risks is essential to success in the modern world,” says Palmer, who also serves as vice chair for basic research at UC San Diego School of Medicine. “Investing money, launching a startup company, running for elected office … these all involve risks.”

Palmer and postdoctoral student Sandra Sanchez-Roige seek to understand the genetic basis of how we either engage in or avoid risky behaviors. In a recent collaboration with a global research team, the UC San Diego researchers asked more than 1 million participants a simple question to assess their overall risk tolerance: “Do you think of yourself as someone who likes to take risks?” They also asked     participants if they took part in specific risky behaviors, such as speeding, drinking and smoking.

The study, published earlier this year in Nature Genetics, uncovered 124 genetic variants associated with a person’s willingness to take risks.

“No single genetic variant on its own meaningfully affects a particular person’s risk tolerance,” Palmer cautions. “Non-genetic factors still matter more when it comes to taking risks. But the combined effect of these 124 genes can be significant.”

Scientists previously thought risk tolerance might be linked to genes related to dopamine or serotonin, neurochemicals that help process rewards and regulate moods. But the team didn’t find that at all in this study. Instead, their results suggested that the neurochemicals glutamate and GABA contribute to variations in risk tolerance. Both are important regulators of brain activity.

The team also found overlap in the genetic influences on risk tolerance and several neuropsychiatric traits, including ADHD and bipolar disorder. “Risk-taking is thought to play a role in many psychiatric disorders,” says study collaborator Murray Stein, vice-chair for clinical research in psychiatry at the School of Medicine. “For example, patients with anxiety disorders may perceive increased risk in certain situations and therefore avoid them unnecessarily. Understanding the genetic basis for risk tolerance is critical to understanding these disorders and developing better treatments.”