Anxiety is an emotion that is functionally related to fear. These emotions originate in a small part of the brain's temporal lobe called the amygdala. Overactivity in the amygdala can lead to anxiety and affective disorders, according to a review published in Dialogues in Clinical Neuroscience. The textbook "Intercellular Communication in the Nervous System" explains that adrenaline is a neurotransmitter involved in activating the "fight or flight" response to threatening stimuli.
Adrenaline Release
Adrenaline, also called epinepherine, is a neurotransmitter that is made and stored in the innermost part, or medulla, of the adrenal glands. The text "Neuroscience: Exploring the Brain" explains that the adrenal medulla is a modified group of sympathetic neurons that sits on top of the kidneys. When the brain perceives a situation to be dangerous, it sends signals to activate the sympathetic division of the autonomic nervous system, releasing adrenaline into the bloodstream. Cells throughout the body respond to adrenaline rather rapidly.
Physiologic Affects
Tissues respond to adrenaline in many physiologic ways. Pupils become dilated, skin becomes sweaty and the heart beats faster. These physiologic changes are meant to prepare an individual to confront an impending threat. However, individuals with anxiety disorders might experience these sensations despite the absence of obvious danger. These physical symptoms are partly due to excess adrenaline secretion.
Chronic Anxiety
Anxiety is a normal feeling when experienced in response to an obvious or impending threat. However, when the body fails to dismount this response following displacement of the threat, an anxiety disorder might be present. Chronic anxiety is associated with elevated adrenaline levels.
Long-Term Effects
The chronic effects of stress and anxiety over time can be deleterious to the brain and the body. One way that the body responds to anxiety is by increasing the production of adrenal hormones called glucocorticoids. These hormones, in turn, communicate with the brain in order to regulate the secretion of pituitary hormones that influence processes such as metabolism, growth and reproduction. The brain is affected by anxiety in many negative ways, explains a review published in Dialogues in Clinical Neuroscience. Anxiety is associated with changes in parts of the brain responsible for learning, memory and higher cognitive functions.
Treatments
The text "Essential Psychopharmacology" explains that anxiety disorders are usually treated with drugs called anxiolytics. Most of the drugs prescribed for anxiety are benzodiazepines, selective serotonin re-uptake inhibitors or serotonin norepinepherine re-uptake inhibitors. Additionally, some patients find that using medications that block the effects of adrenaline, such as propanolol, helps to relieve the uncomfortable physical symptoms of anxiety.
References
- "Dialogues in Clinical Neuroscience"; Protective and damaging effects of stress mediators: central role of the brain; Bruce S. McEwen, PhD; October 2006
- "Intercellular Communication in the Nervous System"; Robert C. Malenka; 2009
- "Neuroscience: Exploring the Brain (3rd Edition)"; Mark Bear, Barry Connors and Michael Paradiso; 2007
- EndocrineWeb: Pheochromocytoma
- "Essential Psychopharmacology (2nd Edition)"; Stephen Stahl; 2002
