One of the largest misconceptions about anxiety is that the disorder is something people "bring upon themselves," a concept that is as malignant as it is incorrect. Adding to the evidence against this isolating stereotype, a new study from the University of Wisconsin, Madison found that the brain function that underlies anxiety and depression may be inherited.
Previous research suggests that anxiety and depression may be at least partially biological, brought on by chemical imbalances in the brain. Studies conducted by the National Institute of Mental Health and the World Health Organization have also found that mental illnesses, such as schizophrenia and major depressive disorder share genetic risk factors and may run in families. The new study takes a look at where anxiety develops in a young brain and whether or not there is a similar brain pattern among close relatives.
Researchers observed a sample of 592 young rhesus monkeys for signs of anxiety in the brain. First they put the monkeys in mildly anxiety-inducing situations -- meant to mimic those experienced by humans -- by invading their space without making eye contact in an effort to monitor a potential increase in stress hormones. Then they had the monkeys undergo PET scans that analyzed metabolic activity in the areas of the brain related to moods. Additionally, the scientists looked at the anatomy of each monkey's brain and compared it to the brains of close relatives.
The brain scans showed that monkeys who reacted to the stressful situation by freezing up or becoming less communicative also showed an overactive metabolism in the brain regions associated with anxiety. Researchers also found evidence that this type of behavior was hereditary: Approximately 30 percent of early anxiety could potentially be passed down by the monkey's parents, according to the study. Other major contributing factors to the development of anxiety include life experience and an individual's environment.
While the study was conducted in young monkeys and not human subjects, these animals are very similar to humans when it comes to what researchers call "an anxious temperament" -- or a reaction to stressful environments.
It's important to note that being predisposed to anxiety does not indicate that you're absolutely going to have anxiety disorder, but rather it offers some insight into how you react to anxiety-producing situations. Experts stress that there are multiple components that contribute to mental health conditions.
The new study's findings overall are encouraging, given that there is a large stigma attached to mental illness. Approximately one in four people will experience a mental health issue at some point in their lives, but 25 percent of people who experience psychological distress believe that people aren't caring or understanding toward those with mental illness.
The study was published in the July 6 issue of the Proceedings of the National Academy of Sciences.