A new study reveals that the function within the brain that produces anxiety and depression seems to be inherited. Experiments with rhesus monkeys (who are known to have ‘anxious temperament’ similar to humans) revealed that when the animals were exposed to slight stress, the monkeys began exhibiting anxious behavior – where they stopped moving or being vocal – while their stress hormones increased. Researcher on the project Dr. Ned Kalin, a psychiatrist, noted that this is similar to what an extremely shy child would do in the same situation.
Kalin and his team analyzed the brains of these young monkeys, and found three regions that were linked to anxiety, which showed a connection to heritability. The study, which was published in the journal of Proceedings of the National Academy of Sciences, reported that approximately 30 percent of the variation of young anxiety produced evidence of heritability.
MSN reports that early anxiety can lead to depression and mental disorders later in life, the goal of the study was to understand the brain function of anxiety in children in an effort to develop early interventions and avoid further progression in the future. The team used PET scans to image the brains of 592 young rhesus monkeys at the Wisconsin National Primate Research Center. Raised in pairs, these animals have differing levels of anxiety. During scans, a stranger would then enter the room the monkeys were in, and avoid making eye contact. This situation, which is really considered a mild level of stress, helped the team determine what occurs in the monkey’s brain when confronted with some anxiety in their daily routine.
As the team knows the heritage lines of all the monkeys in the colony, they were able to trace inherited anxiety behaviors. Kalin and his colleagues discovered 35 percent of anxiety was passed on to the young monkeys, through their parents.
However, the researchers also reviewed targeted brain regions for the monkeys, which produced activity during stressful encounters. They reviewed function and structure against the inherited patterns around anxiety. While structure was not affected, the function of the three brain regions were inherited, and all centered on anxiety. Those three brain regions were: the orbitofrontal cortex, which is behind the monkey’s forehead and is the highest evolutionarily advanced region of the brain; the amygdala, which is an almond-shaped region and located deep within the middle of the brain (connected to fear and emotion); and the limbic system, which is found at the base of the brain.
Kalin notes that there is simply ‘more activity’ in anxious brains, and that his study shows that this over-activity is inherited by children, from their parents. Unfortunately, this also potentially increases the risk of depression, and anxiety later on in life. Kalin also comments that with close to 70 percent of differing risks of these conditions which are not genetic, treatment and interventions are possible to help avoid further complication. Kalin also adds the study can help create new ideas on what can be done to help youth, who may have over-activity in their brain, avoid any long-term negative effects.