Anxious parents DO have anxious children, study suggests

Children may inherit brain traits from their anxious parents that make them susceptible to the same mental health condition, new research suggests. 

Psychologists have long observed patterns of anxiety in families, but most research has suggests that the similarities are due more to ‘nurture’ than genetic ‘nature.’ 

But a new examination of brain structures in anxious families of monkeys, conducted by the the University of Wisconsin, has identified at least one inherited brain circuit that plays an important role in the development of anxiety.

The scientists found that anxious parents and their children shared inherited and uncommonly close connections between parts of their brains that generate a fear response and may prime them for a lifetime of anxiety. 

Children with ‘anxious temperaments’ are often debilitatingly shy and may inherit a brain trait that leads to an over-exaggerated fear response from their parents, a study of monkeys shows

For all the years of research conducted on them, there is still much we don’t understand about where mental health disorders in general – and anxiety in particular – arise from. 

What has become increasingly clear for mental health conditions (just as it has for physical ones) is that most develop through a confluence of genetic and environmental factors.  

One well-established risk factor is what scientists refer to as an ‘anxious temperament’ in early childhood. 

These kids tend to be debilitatingly shy,to experience gripping fear and even nausea at the prospect of the school day and about half of them ‘go on to develop anxiety and depressive disorders later in life,’ explains Dr Andrew Fox, co-first author for the new study. 

Dr Fox, of the University of California, Davis, and his collaborators at the University of Wisconsin decided to look for the brain structures that might distinguish young Rhesus monkeys this temperament from others. 

In previous research, they had found that monkeys with high levels of anxiety also showed signs of extra activity in a part of the brain called the extended amygdala. 

This part of the brain has been implicated in all manner of mental health disorders, including PTSD, anxiety, depression and addiction. 

Its two sub-regions are constantly ‘trying to interface and coordinate between all the emotional information that comes into us with the body’s physiological processes that are necessary to mount a response to those emotions,’ Dr Fox explains. 

‘The “freezing response” [we see in young monkeys] is, we believe, very similar to the sort of behavioral inhibition that we term anxious temperament related to shutting down in the face of what we would normally consider a mild threat and is indicative of this type of anxiety in children.’ 

In their FMRI images of the young monkeys’ brains, he and his team saw that the anxious baby monkeys had the same type of hyperconnectivity between those regions of their brains that their parents did. 

‘Anxiety disorders tend to be partially inheritable,’ Dr Fox says, and because they used group of monkeys with a ‘huge multi-generational pedigree, that allows us to make a pretty good estimate of how similar we would expect family members’ anxieties to be if it were inheritable.’ 

He and his team estimate that the paralyzing shyness and ‘anxiety temperaments’ of the baby monkeys were about 30 percent inherited from their parents. 

‘Because of the nature of this family tree, it is unlikely that [this portion of anxiety] is due to the parent-child interactions, though I’m sure that’s playing a role in anxiety,’ says Dr Fox. 

He cautions that this doesn’t mean they have found the root of all anxiety, or even the root of some anxiety. 

It’s more like their study has confirmed that one brain circuit involved in childhood anxiety (that commonly precedes the disorder in adulthood) is passed at least partially from parent to child in primates similar to us. 

‘Our study is fairly confidently showing that this particular circuit does play a significant role in the development of early life anxieties, and knowing that could help us develop new strategies for helping people overcome anxieties and intervene early in life before children go on to develop these disorders,’ Dr Fox says. 

‘But we’re not going to find the one gene [for anxiety]. And if we really intend to understand these complex disorders, we as scientists and people are going to have to get used to explaining that, and that these discoveries might help one in a hundred people.’