Genes Drive Kids’ Changing Fears


Medically Reviewed by Louise Chang, MD on April 07, 2008 From the WebMD Archives

April 7, 2008 — Scaredy-cat genes make scary things more frightening to some kids than to others. But these fears — and the genes that drive them — change as kids age, a twin study shows.

The idea that genes drive fear isn’t new. Small children tend to be naturally afraid of things, such as snakes, that were dangerous to our ancestors. But they aren’t afraid of many very dangerous things, such as guns or electrical outlets, that our ancestors never saw.

Kenneth S. Kendler, MD, professor of both psychiatry and human genetics at Virginia Commonwealth University, Richmond, led a team that tested this theory using data from a long-term study that followed pairs of Swedish twins from age 8 to adulthood. Data was collected four times: at ages 8-9, 13-14, 16-17, and 19-20.

The twins, and their parents, were asked about how frightened the children were — ranging from not at all scared to absolutely terrified — of a long list of items including fear of snakes, fear of spiders, fear of heights, fear of flying, and other things often seen as scary.

“Our question was, how important are genetic factors in the fears of these children?” Kendler tells WebMD. “The answer is, pretty important. I was not completely surprised by this — but I didn’t expect the results to be as dramatic as they are.”

Child’s Development, Environment Affect Fear Genes

What surprised the researchers was that though genetic factors strongly influenced children’s fears, these factors changed over time.

“One model of genetic influence is you get a hunk of genes from mom and dad and they make you a more fearful person or a less fearful person. That is not what we saw at all,” Kendler says. “We saw something much more dynamic. When you are a 7- or 8-year-old, the genes acting on your fears are different than those that act on your fears when you are going through puberty. And they continue to differ as you go into young adulthood.”

This makes sense in terms of evolution, Kendler says.

“Let’s go back 500,000 years ago: What are the sorts of things a 7- or 8-year-old might be afraid of in their environment? It might be a snake that might bite them. It might be the dark, because if you are 7 and lost and it is dark and can’t get back to your parents you are going to be meat for the cheetahs or hyenas,” he says. “But by the time you are 20 years old the kinds of risks you are going to be afraid of are different. It might be social factors — such as other people who are going to brain you if you are after their girlfriend.”

Kendler believes that what is true of normal fears is also true of the more intense, disabling fears known as phobias. That is, he feels the genetic influence on these disorders changes through childhood.

“Phobias represent an extreme where the fear is high and then it begins to either incapacitate or substantially interfere with life,” he says. “I cannot say for certain the patterns we saw in this study extrapolate to phobias, but from other data I can say that the same factors that govern normal fears seem related to predisposing a person to having more phobic disorders.”

Joanna Ball, PhD, assistant professor of psychiatry and behavioral sciences at New York’s Montefiore Medical Center, works with fearful children. Kendler’s findings are in line with her clinical experience.

“As kids get older, their ability to make sense of things matures,” Ball tells WebMD. “Maybe they are frightened of thunder at age 8, but as they get older, they see people don’t typically die in thunderstorms. So they can call on their experience when faced with thunder. But as they get older, they understand other frightening things and may develop fear of illness, fear of death, or even fear of money issues.”

Genetic influences, Ball says, are just one of many factors that contributes to a child’s fearfulness.

“Everyone is predisposed to a lot of things, but how that manifests depends on what environmental experiences you have and what developmental stage you are in,” she says. “If you are prone to something, whether it is anxiety or phobia, a lot has to do with where you are developmentally and in terms of your environment.”

Helping Children Deal With Fear

When children are afraid, just telling them to get over it doesn’t help. But it also doesn’t help to give in to a child’s fear.

“Listen to the kids, let them express themselves. If they feel heard, it makes a big difference,” Ball says. “But the more parents give in to the fear and make accommodations, it gives the fear more credibility. Parents come to me, and the kids are sleeping in the parents’ bed, the parents are sleeping in the kid’s bed, and the parents have so accommodated the fear it seems valid. Instead, help the kids produce evidence: Look under the bed with them, for example.”

Being fearful is a normal part of childhood. There really are a lot of things to be afraid of, and a lot of things kids need to be reassured about.

Professional help is needed if a child’s fears impair his or her normal function.

“Warning signs are when a child starts to be fearful about leaving the house, is unable to go to school, gets very clingy, has sudden changes in mood, or is fearful of a lot of different things,” Ball says. “When fears get in the way of them being a kid is when you want to seek help.”

The Kendler study appears in the April issue of Archives of General Psychiatry.

Show Sources


Kendler, K.S. Archives of General Psychiatry, April 2008; vol 421: p429.

Kenneth S. Kendler, MD, Banks distinguished professor of psychiatry andhuman genetics; director, Virginia Institute for Psychiatric and BehavioralGenetics, Virginia Commonwealth University School of Medicine, Richmond.

Joanna Ball, PhD, assistant professor of psychiatry and behavioral sciences,Montefiore Medical Center, New York.

© 2008 WebMD, LLC. All rights reserved. View privacy policy and trust info

search close