Causes of Anxiety Disorders

and Selective Mutism

This chapter (on the causes of anxiety disorders) actually goes on for over 30 pages in my book, but I will keep it short on the website to just this one page!


Evidence shows that genes influence brain chemicals and alter brain structure, which then can lead to anxiety disorders. In addition, chronic and excessive anxiety actually changes the structure of different sections of the brain, so it may be a “chicken/egg” phenomenon: Did the altered brain structures and chemicals cause the anxiety, or did the anxiety cause altered brain structure? It’s unclear in some cases, but considering environment is known to cause anxiety, in addition to genetics, it’s possible both ways! 


The multifaceted origination of anxiety disorders and maintenance of anxiety disorders possiby comes from a combination of personality, temperament, environmental factors, genetics, brain chemicals, brain structure, learned behavior, and cognitions. These can all play a role in either causing anxiety or helping to maintain the anxiety. Because all of these issues are intertwined, they all have an effect on each other, which makes anxiety disorders so complicated! 


What Does Not Cause SM?

It should be noted that to date, trauma and isolation are NOT environmental factors that have been linked to causing SM. There is more discussion on this in the actual book to gain a better understanding as to why these do not cause SM.



There actually are specific temperamental and personality characteristics that are linked to a higher risk for developing anxiety. It’s well documented that this includes concepts such as negative affectivity (neuroticism), harm avoidance, and behavioral inhibition, which is of particular interest to me because people with SM tend to be extremely behaviorally inhibited.


Environmental Factors

There are some environmental factors to take into consideration with SM. These include but are not limited to: medical issues the first year of life, speech delays, hearing impairment, English as a second language, parenting behaviors, and parenting styles. In the book, I give examples of these situations, but I also discus how NOT every child who has a shy parent, a speech delay, or a hearing impairment, etc. is going to develop SM.


For instance, most children with a speech delay will not develop SM: About 7-8% of US kindergartners are diagnosed with a specific language impairment, but only .03%-1% of the population has SM, and of those .03%-1%, less than half have a speech or language delay.


It seems as though the children who are genetically and biologically predisposed to anxiety disorders are more vulnerable and more affected by their environmental circumstances,  leading to a higher chance of developing anxiety disorders.




At this time, there is still much more unknown than is actually known about the genetics of anxiety disorders, but based on identical twin studies of anxiety, it seems as if genes do play a major role, in addition to environmental factors affecting these genes in various ways. Therefore, anxiety symptoms seem to be the result of many genes and systems communicating with each other, but when errors occur, the systems regulating emotionality and behavior are interrupted.


There are studies documenting some genes and alleles affect things such as serotonin, the hippocampus, and other brain areas causing anxiety. It is very important to note: If a child with SM has no other family members with SM (which is likely the case), it doesn't mean it's NOT genetically based for that child- There are many different anxiety disorders, and they can be passed down genetically without being the same exact anxiety disorder. Remember, all anxiety resides in the same place in the brain.


Brain Chemicals

In general, with the classification of anxiety disorders, it appears as if the neurotransmitter systems of serotonin, noradrenaline/norepinephrine, and glutamate and gamma-aminobutyric acid (gaba) are primarily affected. In my book, I explain what these brain chemicals do, what they are responsible for, and also how these neurotransmitters are affected by genetics, and how they can contribute to anxiety. If the person is not producing enough of these chemicals, transporting them efficiently, retaining enough, or balancing each other out, anxiety disorders can occur.



Brain Structure

Structurally, the limbic system in the forebrain is most affected by anxiety disorders because it plays a central role in processing all anxiety-related information. The limbic system structures of the hippocampus, amygdala, and hypothalamus are of particular importance in anxiety, especially due to the "fight, flight, freeze" mechanism. MRI's show these structures can appear different in people with anxiety! Sometimes the genetics cause these structural differences, and sometimes the anxiety actually causes the structural changes. In my book, I go into great detail on these structures and why they play a role in anxiety, and specifically in SM.


Learned Behavior

The DSM-V states that both SM and social reticence (being reserved) can also originate from learned behavior when the child’s parents model shyness or social inhibition, and the DSM states that SM can originate from overprotective parenting styles. The child may learn to be fearful or overly cautious of novel experiences from observing her parents’ responses to these types of situations. In my book, I discus how this is actually rare to cause SM, but in combination with other factors, it is something to consider in leading to SM or maintaining SM.



Because cognitive behavioral therapy (CBT) is used to treat anxiety disorders (including SM), some wonder if cognitions can cause anxiety disorders.


CBT was developed in the 1960’s by psychiatrist and leading professor for the University of Pennsylvania School of Medicine, Dr. Aaron T. Beck, M.D. In reading his book, Anxiety Disorders and Phobias: A Cognitive Perspective, it seems that the primary pathology during an anxiety disorder is in the cognitive apparatus, although cognitions do not cause anxiety disorders. Rather, Dr. Beck claims that cognitions are “far from being a cause of anxiety disorders.” He states that the “cognitive processes constitute a major mechanism by which the organism adapts itself to the environment. When a variety of factors interfere with the organism’s smooth operation, it becomes the mechanism through which anxiety disorders or other disorders are produced,” (Beck and Emery 1985, 86). This means cognitions don't cause anxiety disorders but they contribute to them and help maintain them, so altering cognitions can lead to anxiety symptom reduction.