A propensity to anxiety is a physical, inherited illness, as is migraine. It is not psychological! By viewing certain key structures in the brain, such as the amygdala, one can almost predict who has anxiety. Even at age 5, in a child with separation anxiety, the amygdala is larger than normal, and fires more often. Anxiety could almost be termed “the overactive amygdala syndrome.”
The amygdala is part of the larger limbic system. Other limbic structures include the thalamus, hippocampus, hypothalamus, along with the anterior cingulate gyrus and the orbitofrontal cortex. The amygdala warns of incoming dangers, after processing multiple incoming sensory inputs. Amygdala connections are vast, with direct connections to:
1. The hypothalamus, triggering fight-or-flight responses,
2. The locus ceruleus (in the pons), increasing the output of norepinephrine, with
a resulting rise in blood pressure, heightened response to fear, and level of
3. Various other structures, such as the periaqueductal gray matter, modulating aspects of our fear response. The amygdala regulates the tone of our emotions, and is hyper reactive in anxious patients.
The hypothalamus initiates our fear response; when it overreacts, the resultant anxiety is out of proportion to the actual threat. The hypothalamus may trigger an overproduction of corticotrophin release factor, adding to the anxiety response. The thalamus is our integrating relay station, with a vital direct connection to the amygdala. The thalamus plays a vital role in regulating sleep and eating patterns, which often are disrupted in anxious patients. The hippocampus is crucial for memory, and it holds the memories that trigger the fear response. It is also important in the development of post-traumatic stress disorder by holding on to the traumatic memories.