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Wonder how your kids show the same signs of anxiety as you? A new study has found the answer. It says that anxious parents are more probable in passing their anxiety on to their off springs.
Researchers from the Department of Psychiatry and the Health Emotions Research Institute at the University of Wisconsin performed a study on the extended family of rhesus monkeys – having the similar history of anxious off springs of anxious parents like their human counterparts, that showed how an hyperactive brain circuit consisting of three brain regions succeeded from generation to generation may result in developing anxiety and depressive disorders.
Ned Kalin who is the chair of psychiatry at the School of Medicine and Public Health at University of Wisconsin and the senior author of the study said, “Over-activity of these brain region are inherited brain alterations that are directly linked to the later life to develop anxiety and depression.”
Photo Credit: University of Wisconsin
Earlier research by Kalin and his group showed that anxious nature is inherited, and explained the brain circuits included in it. About half of the children who display tremendous anxiety head on to grow stress-related psychiatric disorders, later in their lives.
Monkeys can also have an anxious nature and deliver their anxiety-associated genes to their off springs.
Kalin along with Andrew Fox, coauthor of the study and other colleagues studied almost 600 young rhesus monkeys from a massive multi-generational family. They found that about 35 percent of disparity in anxiety-like propensities is explained by family history.
However, the research team didn’t know which brain areas were accountable for forwarding anxiety from one generation to other. To learn that they revealed the monkeys to a gently threatening situation – introduction to a stranger who didn’t make eye contact with them, something a child would also come across. They used imaging processes during this meeting, usually used in humans called “positron emission tomography” (PET) to recognize the brain areas, whose increased metabolism foretold each creature’s level of anxiety.
Under minute examination of understanding the process of individual disparities in brain functions and anxiety-associated behavior, coming down the family tree; the research team recognized brain systems accountable for the parent-to-child communication of anxiety-associated behavior. Utilizing this “genetic correlation” method, they discovered the neural circuit where metabolism and early-life anxious nature are probable to have the same genetic basis.
The examination disclosed that three survival-linked brain areas formed the brain circuit that was accountable for conveying anxiety from parent-to-child. These areas were situated in the brain stem – the amygdale, the limbic brain fear center and the prefrontal cortex that is in charge of higher-level reasoning and is completely matured only in humans and their primate counterparts.
Kalin says to a particular extent “anxiety can provide an evolutionary advantage because it helps an individual recognize and avoid danger.” However, when the brain circuits are hyperactive, it becomes an issue because it can lead to anxiety and depressive disorders.
The research team also found that it as the purpose of these brain structures instead of their sizes that was accountable for the genetic transmission of an anxious nature. This research helps in explaining the possible part of genes in brain function albeit the quest for the “genetic underpinnings of anxiety” has been indefinable.
“Now that we know where to look, we can develop a better understanding of the molecular alterations that give rise to anxiety-related brain function,” Kalin said.
He added that this is a “big step in understanding the neural underpinnings of inherited anxiety,” and starts to give them more “selective targets for treatment.”
The paper titled “Intergenerational Neural Mediators of Early-Life Anxious Temperament” was funded by the National Institute of Mental Health (NIMH) and is being published this week in the Proceedings of the National Academy of Sciences (PNAS).
A 2012 report by University of Queensland found that globally one in 13 people suffer from anxiety. Based on a two different surveys of clinical anxiety and depression that were performed across 91 nations, consisting of 480,000 people they found that anxiety disorders were more ordinary in Western countries than non-western ones while depressive disorders were more seen in non-western countries than their Western counterparts.
10 percent of people were affected by anxiety disorders in North America, Western Europe and Australia/New Zealand as against 8 percent affected in the Middle East and 6 percent in Asia.
In case of depression, Asian and Middle Eastern countries like India and Afghanistan recorded the most cases with 9 percent people affected as against 4 percent in North and South America, Australia, New Zealand and even East Asian countries like China, Indonesia and Thailand.