Anxiety disorders seem to rely greatly on one’s genetic abilities to retain memories which evoke feelings of upset and fear, according to a study from the Karolinska Institutet in Sweden and University of Greifswald in Germany. The research suggests that people with anxiety disorders are quick to learn to fear a stimulus and then find it difficult to lose the memory of this fear over time due to polymorphisms in two genes, being the serotonin transporter gene and the gene for the enzyme COMT.
The researchers tested a group of volunteers who were shown two different pictures a number of times. A mild electric shock was given after the showing of one of the specific pictures and because of this, the participants learned to fear this picture, which was evaluated through physiological responses. The participants then repeated this experiment the following day to test if the fear could be overcome, however, this time the electric shocks were not used. If the physiological responses of fear had disappeared, it signified the fear had been overcome.
Blood samples of the volunteers were then collected and the particular characteristics of the aforementioned genes were identified. Those who still feared the electric shock picture had a common polymorphism in their serotonin (the brain chemical associated with mood regulation) transporter which led to less serotonin being cleared away. These participants received a very strong physiological response to the electric shock picture as they had developed strong feelings towards its sight. Furthermore, volunteers with gene coding resulting in greater amounts of the COMT enzyme, responsible for fear extinction, were more capable of erasing the memory of the fear than those with the variant gene.
This research is very interesting as it addresses why some people may be more susceptible to anxiety disorders, due to their ability to learn and remember threat and trauma in their lives, as a result of these particular polymorphisms in their genes.
References:
Lonsdorf et al. Genetic Gating of Human Fear Learning and Extinction: Possible Implications for Gene-Environment Interaction in Anxiety Disorder. Psychological Science, 2009; 20 (2): 198 DOI: 10.1111/j.1467-9280.2009.02280.x
Science Daily LLC 2009, Genetics Of Fear: Specific Genetic Variations Contribute To Anxiety Disorders, Study Suggests, viewed 20 March 2009 http://www.sciencedaily.com/releases/2009/03/090310161503.htm
Woodard 2009, Speculative Anxiety, viewed 20 March 2009, http://speculativeheresy.wordpress.com/2009/01/17/speculative-anxiety/
By 42049193
