The Brain and Anxiety: Is there a Worry Center?
Sky news in the UK recently proclaimed "Scientists have pinpointed the "worry center" of the brain for the first time in a discovery that could lead to new, more effective treatments for anxiety and depression".
The article goes on to discuss how a new study done at Kings College in London shows that mri scans of people made anxious through electric shock have identified the hippocampus as the source of anxiety (Moore, 2010).
Another recent news article talks about how this study, funded by the insurance company AXA , will likely lead to new and promising drugs which target the hippocampus (Adams, 2010).
These claims are not entirely accurate, as we have been investigating the brain pathways involving the hippocampus and amygdala as it relates to fear, stress, and anxiety for quite some time. However, neuroimaging studies continue to be helpful in understanding anxiety and what brain pathways are involved. Anxiety is so complex and each diagnosis (phobias, panic disorder, ocd, post traumatic stress disorder, generalized anxiety disorder) is different.
One thing we do know is the brain looks and works differently in people that have anxiety, and that the brain itself is capable of changing its structure when people heal from anxiety. As a therapist, it’s important for me to keep current on this research because I want to do what is most likely to heal my clients. The more I know the better off they are.
In the 80's anxiety brain studies focused on a part of the brain called the locus ceruleus. It was generally believed that this was a major player in the source of anxiety. However, research did not really bear this out to be true. Additionally norepinephrine, the neurotransmitter most closely involved with the locus ceruleus, was not impacted by the drugs that help anxiety. Drugs that treat anxiety best seem to be those that target serotonin, so researchers knew something was wrong with the theory. This part of the brain was involved in the stress response for certain, but exactly how it relates to anxiety is unclear. Scientists began to study the hypothalamus and the amygdala and hypothalamic-pituitary-adrenocortical axis - (HPA) to better understand how the brain is involved in anxiety.
Currently most of the research being done on the brain and its relationship to anxiety focuses on the amygdala and the hippocampus.
Imaging studies are amazing. We know that the amygdala is involved in the fear response from MRI studies that show in healthy people's brains the amygdala is activated when they are shown pictures of fearful facial expressions. Typically it has become the part of the brain studied when exploring fear.
There are many studies documenting the relationship with the amygdala and anxiety. One imaging study demonstrated that 17 children with anxiety compared with 17 without anxiety, had a smaller hippocampus.
The amazing thing here is that after medication OR THERAPY, the children's amygdalas grew (Milham MP, 2005)!
The hippocampus has more to do with verbal memories and emotions.
Neuroimaging has shown that those who experience post traumatic stress disorder have a reduction in the size of the hippocampus. If the hippocampus is impaired, the individual is thought to be less able to draw on memory to evaluate the nature of the stressor (McEwen, 1998). This makes much sense in our understanding of post traumatic stress disorder!
Although we don't entirely understand the relationship between the amygdala, hippocampus, and the anxiety disorders, each day more and more is explored. It is exciting for us to keep updated on how therapy can help with anxiety disorders and how the brain actually demonstrates its effectiveness.
Adams, S. (2010, NOvember3). MRI brain scans 'could lead to targeted anti-depressants'. Retrieved November 7, 2010, from Telegraph.co.uk: http://www.telegraph.co.uk/health/8105697/MRI-brain-scans-could-lead-to-targeted-anti-depressants.html
McEwen, B. (1998). Protective and Damaging Effects of Stress Mediators. N Engl J Med , 171-179.
Milham MP, N. A. (2005). Selective Reduction in Amygdala Volume in Pediatric Anxiety Disorders: A Voxel-Based Morphometry Investigation”. Biological Psychiatry , 57 (9), 961-6.
Moore, T. (2010, NOvember 4). Brain Scan Study Locates Source of Anxiety. Retrieved November 7, 2010, from Sky News: http://news.sky.com/skynews/Home/UK-News/Scientists-Pinpoint-Brain-Worry-Centre-Could-Lead-To-New-Treatments-For-Anxiety-And-Depression/Article/201011115794881?lpos=UK_News_News_Your_Way_Region_9&lid=NewsYourWay_ARTICLE_15794881_Scientists_Pinpoint_Brain_