Imagine it’s a hot day and you are standing on the edge of dock, looking down into the cool water below. You want to jump in, but you are suddenly overcome with terror at the thought of being in the water; your heart starts racing, you can barely breathe, you start sweating, and your first instinct is to run back to the safety of shore. This unreasonable fear you have in response to water is likely a phobia, aquaphobia to be exact. Phobias are an extreme and irrational fear when exposed to some specific stimulus like insects, heights, or water. Interestingly, those who suffer from phobias recognize their fear is irrational and there is no real threat of danger, yet they will still avoid any contact with their phobic trigger. This begs the questions, what causes phobias? And what is going on in the brain to cause such extreme reactions to often innocuous objects or situations? With somewhere between 5-13% of Americans experiencing a type of phobia at some point in their lives, the neurological basis of phobias and fear is certainly worth investigating. Here are some of the most common types of phobia that are encountered:
According to the DSM-IV, there are 4 categories of phobic stimuli; animal, situational, blood injury, and nature-environment. The cause of different types of phobias is still debated though. One well proven theory is that phobias develop as a result of an unpleasant or traumatic experience in childhood. For example, if a child had an unpleasant experience in a confined space, they may develop claustrophobia. Additionally, a child may witness a family member’s phobia and develop the same phobia. Still, it cannot explain how agoraphobia or social phobia arises; the causes of these are still somewhat of a mystery. Some researchers believe the disorder could be a combination of life experience, brain chemistry, and genetics.
So now we have established that one likely cause of phobia is conditioned fear; it is learned through a family member or through a traumatic experience. So what is going on in the brain during this extreme fear response? A lot of what happens has to do with the amygdala, which triggers the release of “fight or flight” hormones as well as areas in the frontal lobes. The anterior cingulate cortex and the medial prefrontal cortex have been shown to be involved in processing and responding to negative stimuli while the ventromedial prefrontal cortex monitors the amygdala’s response to emotional stimuli or fear. However, in patients suffering from a phobia, these areas appear to function improperly. Here is a map of some of the areas involved:
So, rather than being a system sensitive only to harmful stimuli, the improperly functioning circuits create a fear response to neutral stimuli. As a result, when somebody with a phobia encounters their phobic trigger, the activity in their amygdala spikes. A full on fight or flight reaction occurs even if the stimuli is relatively neutral and harmless.
Want to know more about phobias and the neuroscience of fear? Check out this video!
Sources:
http://www.medicalnewstoday.com/articles/249347.php
http://brainblogger.com/2010/04/22/the-neurobiology-of-social-anxiety-disorder/
On Psychology and Neuroscience 
I found this article particularly interesting because I have read many different articles that try to explain the nature of different phobias. While I was abroad last fall, I went to a lecture series where the speaker presented his research with participants who had experienced phobias. He explained how one of their main goals was to get the participant to face their phobia by the end of training. I found this impossible to believe until we watched a video that examined the entire procedure. My intense fear of snakes (not sure whether to consider it a phobia) is quite frightening. I know that there are limited circumstances in which I would actually have to come into contact with snakes but just the thought sends shivers through my whole body. Growing up my friends would always prank me with toy snakes and I would freak out! I am not sure if I could go through one of the simulations where you come into contact with your phobia and tackle it head on. Maybe one day I will get the courage.
-Taysir Jama
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After reading your post I realize that it is so easy to focus on a phobia in its current existence rather than delving into where the phobia developed. I have one friend who, I feel pretty confident saying, has emetophobia. While the phobia itself is something that I’ve considered when she’s been feeling sick, I can’t remember ever talking to her about where she thinks this phobia came from. I suppose that this ambiguity lends itself to the uncertainty that still exists regarding the basis of phobias. I too am left curious as to how brontophobia, for example, could be genetically conveyed. It seems to make more sense that someone could be born with a genetic disposition, such as improperly functioning fear circuits, that could then be negatively triggered by a traumatic event…thus creating a phobia. This sort of approach indeed encompasses the experiential, chemical, and genetics-based theories that you suggest contribute to phobias, and it will be interesting to see where neuroscientists take this research next.
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This is a very interesting topic (I can definitely relate). I have always been afraid of spiders, but I have noticed that my fear grows with every interaction with a spider. I know that one way to over come phobias is to expose the person to their fear. Have you looked into research done with people who have overcome their fears?
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I found this post very interesting. I have never experienced having a phobia but my best guy friend had multiple when we were growing up. He loved to climb, but was afraid of heights. He would love to travel, but was afraid of flying. It did not make sense to me that someone who was so good at climbing and enjoyed it could be so scared when they got to the top. I also could not figure out why flying scared him so much if he never flew before. This post mentions phobias being inherited from parents. My friend’s dad also had a phobia for flying. I feel this article does a nice job touching on that phobias may be from not just experimental stimuli but also chemical and genetics. I feel that it is easy to say that someone must have had a traumatic conditioned experience, but is that the real reason? It would be interesting to test genetics and chemicals in children that have developed phobias that parents have and compare that to their siblings that do not have the phobia.
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I think phobias are a really interesting topic, mostly because the people who have them recognize that they are irrational and that perhaps they shouldn’t have the fear or fears. You mention that the circuitry in the brain is wired to respond not only to harmful stimuli but to neutral stimuli as well. I wonder, is there any research on this? Has there been any extensive research examining phobias and how they manifest themselves? I think this would be a really interesting area to further delve into. I know several people with arachnophobia, but I also have friends who are afraid of small animals, and I wonder where that type of phobia comes from more than the arachnophobia. It seems likely that a traumatic interaction with a spider or a small animal would trigger the phobia, but I wonder if certain brains are prewired to respond that way to neutral stimuli? It would be really interesting to examine phobias further, in the direction of where they originate.
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I found it interesting that most phobias develop from an early age. Phobias affect millions across the world and in some cases can lead to severe anxiety, panic attacks, and even depression. Phobias can be serious issues that require extensive therapy to relieve. So, if phobias originate from our youth, is there a way to protect ourselves? It’s clear that their affects are long-lasting, thus it’s important that psychologists find a way to address phobias early on to nip it in the bud. I know several people with phobias, family members included, and I have seen how debilitating they can be. It’s interesting too that people with phobias recognize how irrational their fear is, yet they still can’t convince themselves to move past the fear. I think exposure therapy is a good way to fight phobias and help people who have them because while it will be difficult at first, hopefully it will eventually lead people to build up a better protective wall around themselves so that they won’t let phobias take over their life like they used to.
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