Over the last several decades, there has been a significant increase in the number of children who are diagnosed with autism, or autism spectrum disorder (ASD). According to the Center for Disease Control, in 2012 the rate of children diagnosed with Autism grew by 78% since 2002 (Kuehn, 2012). This can also be supported in the growing prevalence we see of ASD in minority groups. In that same CDC study from 2012, it was reported that the number of African-American children to be diagnosed with ASD had risen 91%, and 110% in Hispanic children.
This can be contrasted from the number of White children diagnosed with ASD, which had risen 70% (Keuhn). These numbers are truly shocking, as they are a clear indicator of the sheer prevalence of Autism at this time. Many questions also arise as to what may be the cause of this rise in ASD. In answering these questions, we may be able to provide helpful treatments to those with ASD who may struggle in certain aspects of their lives. From a psychological perspective, there are many ways by which the answers could be researched. One means by which to study the prevalence of this disorder is by understanding the causes.
Scientists have been interested in the difference between the brain of an autistic child versus the brain of a ‘neurotypical’ child. As a result of their curiosity, these scientists found several very interesting differences between the two brains. One major difference they found was that the brains of the autistic children between the ages of 2 and 4 years of age had a greater volume than the other children (Ecker, Bookheimer, & Murphy, 2015). Later research done by this group of scientists found the possible cause for this difference in brain mass.
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A major difference they found was that the brains of the autistic children grew and matured at a quicker rate than did the brains of the children who were not diagnosed with autism. How did these scientists come to that conclusion? They studied the autistic children’s brains through functional magnetic resonance imaging (fMRI), and found differences in the brain structure between the autistic and non-autistic children. The results were fascinating, as it was found that there was a greater number of cortical folds in the brain of the autistic children, which scientists have said is most likely a result of trying to fit a larger brain within the proximity of the skull.
Several differences in the cortical folds were found exclusively among the brains of the autistic children, including: macrogyria, polymicrogyria, and a significant increase of gyri in the frontal lobe (Ecker, Bookheimer, & Murphy, 2015). Macrogyria is what scientists understand to be enlargement of gyri in the brain, whereas polymicrogyria is defined as the very small folds in the brain. In the brains of the autistic children, one or both of these types of gyri formation was found. The means by which these types of gyri formations came to be is mainly understood by scientists to be a result of an atypical growth pattern of the brain. These findings are consistent with the earlier findings that children with autism have greater brain mass than their other 2 to 4- year counterparts.
In addition to the mass of these young children with ASD being slightly different than other children their age who do not live with the disorder, there is a difference in the functionality of certain important parts of the brain. One of these great differences is that there has been a irregularity in the way that both the Broca’s and Wernicke’s areas in children with ASD function in relation to those who are ‘neurotypical’. The Broca’s and Wernicke’s areas in the brain are mainly tasked with those skills of speech as well as speech development. Both of these areas have been found to be abnormal in the brains of these children with ASD, which scientists believe may account for some of the social difficulty that children with ASD often experience (Ecker, Bookheimer, & Murphy, 2015).
Another important difference that these fMRIs could see in the ASD children was that their brains also had abnormalities in both the frontotemporal regions as well as the amygdala. What they were able to find is that children with ASD often have an enlarged amygdala when compared to other non-ASD children. It is commonly understood that the amygdala is the seat of emotional processing. This is an interesting find as it allows a possible explanation for the difficulties that many ASD children have in the processing of emotion. It is also known that oftentimes children with generalized anxiety disorders also have an enlarged amygdala, which is also related to their inability to effectively process emotions. Scientists are still trying to understand the correlation between the enlargement of the amygdala and its impact on emotional processing (Ecker, Bookheimer, & Murphy, 2015).
There is yet another set of parts of the brain which show differences in the brains of ASD children. It has been found through fMRI that the brains of children with ASD have abnormal functioning in the orbitofrontal and caudate nucleus parts of the brain. In fact, it has been found that these children have an enlarged caudate nucleus (Ecker, Bookheimer, & Murphy, 2015). The caudate nucleus has several important functions in the brain. One of these functions is that the caudate nucleus helps the brain learn new things. The caudate nucleus also aids in the making and keeping of memories, as well as communication skills. What is interesting about the caudate nucleus is that it is also implicated in OCD sufferers (Healthline). Both ASD and OCD individuals have similar behaviors, including those of a repetitive nature. They also tend to become obsessive about certain thoughts that others who are more ‘neurotypical’ may not display. It would make sense then that these repetitive, obsessive behaviors are seen in those with ASD, as often that part of their brain (caudate nucleus) is enlarged more than is typical in the brains of those who are non-ASD.
It has also been found that children with ASD show a decrease in activity in certain areas of their brain. The parts of their brain which show a decrease in activity are those which are implicated in both emotional processing and social cognition, which include: amygdala, inferior frontal cortex, as well as the temporal-parietal junction (Ecker, Bookheimer, & Murphy, 2015). It has also been found that the decrease in activity in these parts of an ASD individual differ based on the severity of the disorder itself. Among those with ASD, the level of activity in these parts of the brain will vary from case to case. But it can be said that in general, there is a significant decrease in neural activity in these parts of the brain between the ASD and non-ASD individuals.
At this time, there are several different theories surrounding the cause of ASD. A prominent theory is that of hyperserotonemia. This term essentially means that there is an increase of serotonin in the body. Serotonin, which can also be noted as 5-hydroxytryptamine (5-HT), is vital to the human body. A great deal of processes of the central nervous system are aided by serotonin. Examples of these processes are: circadian rhythm, pain sensitivity, mood, aggression, memory, and learning just to name a few (Sodhi & Sanders-Bush, 2004). In addition, serotonin has a very important role in the development of the brain in the womb. Scientists have seen the presence of serotonergic neurons in embryos as young as 5 weeks old (Sodhi & Sanders-Bush, 2004).
With the ability to see these neurons in the brain from such a very young age, scientists have been able to determine the importance of serotonin in the brain development of even the smallest humans. In the case of individuals with ASD, it has been found that there is a specific gene (Gly56Ala) which is essentially a mutation of the 5-HT gene. This gene mutation has been found to cause rigid behaviors in children with ASD, as well as what is called insistence on sameness behavior (Levin-Decanini, Maltman, Francis, Guter, Anderson, Cook, & Jacob, 2013). It can be said then that one of the best means to which help symptoms of those with ASD is to look at the means by which serotonin can be regulated.
Further research on the topic of how serotonin metabolism in ASD individuals helps us to further understand what treatments are possible to help relieve some of the symptoms. In many cases, the symptoms of ASD can case great dysfunction on one’s life. The implications are often substantial in the way they effect and individual’s social functioning. In addition to social functioning being impaired, it is also possible that the repetitive behaviors which often accompany an ASD diagnosis can cause distress to an individual and their lifestyle. Therefore, it is important that the findings scientists have been able to attain are used as a means by which treatment can be improved in the future.
In fact, some of the findings of scientists have allowed for greater treatment options being offered on the basisof helping to balance the hyperserotonemia seen in ASD patients. Seeing as there is an excess of serotonin in the systems of ASD patients, the goal would be to find a means to help bring the levels of serotonin to a more stable level. One very helpful treatment has been the use of SSRIs, or serotonin synapse reuptake inhibitors. These SSRIs commonly used include: fluoxetine, venlaflaxine, or fluvoxamine.
These are just a few of the several options for SSRIs which can be prescribed. Another interesting possibility is treating ASD patients with both clomiparine, which is often used to treat those who suffer from OCD. It is often seen used alongside an SSRI for better results (Giordano & Lombardi, 2009). These types of treatments with SSRIs have been found to be beneficial in the control of some ASD symptoms. The large majority of the improvement was seen in the social functioning of ASD patients while being treated in this manner.
To have an understanding od ASD allows better treatment options for those who struggle with the myriad of symptoms that may come along with the disorder. As discussed earlier, the prevalence of ASD has been growing rapidly in the last several years. We can see these greater rates of prevalence growing at quicker rates within minority communities. Understanding the disorder and the possible causes allow scientists a better look at what the treatment options can be for these children. It is imperative for scientists to continue to study the way that ASD begins to affect the brain of children, as it allows for treatment options that come earlier in their lives. The idea is that if treatment is provided earlier in these children’s development, that their progress and trajectory of positive outcome will be increased.
As we have seen through the above research, ASD affects many parts in the brain. The disorder also effects the level of serotonin in the brain, which also affects several parts of the brain. Having the knowledge that scientists now know is that the level of serotonin is a large part of the symptoms of ASD, professionals can find means by which to balance serotonin levels and improve the quality of life these children with ASD are able to have. Many symptoms, the majority of which have large social implications, can greatly be improved through SSRI treatment.
The wonderful thing about treatment of ASD by means of SSRIs is that it does not require any invasive treatment. Instead, SSRI treatments allow for the brain of the ASD patient to balance themselves. While this treatment can be beneficial on its own, it would also make sense to allow for some behavioral therapy to be used in conjunction. With both treatments being employed, one would hope to see results that would be even greater and more long-lasting. Having both treatments may be beneficial, but not absolutely necessary to see improvement in ASD symptoms. Another incredible advantage to autism symptoms being treated through SSRIs is that it is much more accessible to all groups of individuals, where minority families are often not given the same privilege of healthcare.
With the ability for this treatment to be more accessible, more children with ASD can get the help they need at an earlier age. This is incredible news for both the families of these children, as well as the children themselves. We know the goal of the treatment is to help decrease the severity of ASD symptoms. These children who are able to receive SSRI treatment are more likely to have fewer social issues, and oftentimes display fewer repetitive behaviors than those children who are not taking SSRIs. As explained earlier, serotonin is a neurotransmitter that is imperative to several of the brain’s functions. When SSRIs are used, the brains of the children with ASD are able to have a more regulated amount of serotonin. The result is that these children are able to have more regulated behaviors.
At this time, it may not be possible to stop the rising rates of prevalence in autism. However, through means of research of the brains of autistic children, new means of treatment can be found. The current treatment of ASD treatment with SSRIs is beneficial, but it may be possible to find an even more efficient treatment technique in the future.
References
- Giordano, A. C., & Lombardi, V. A. (2009). Causes and Risks for Autism. Nova Science.
- Levin‐Decanini, T., Maltman, N. , Francis, S. M., Guter, S., Anderson, G. M., Cook, E. H. and Jacob, S. (2013), Broader autism subphenotype relationships. Autism Res, 6: 621-630. doi:10.1002/aur.1322
- Sodhi, M. S., & Sanders-Bush, E. (2004). Serotonin and brain development. International Review of Neurobiology, 59.
