person with difficulty and questions in studies

Alexithymia and Autism : how do they interact?

By Georgia. C

Alexithymia is the term commonly used to describe individuals who have issues interpreting and expressing their emotions. It is suggested that around 1 in 10 people have alexithymia [1], however, its prevalence is much higher in individuals who are on the autism spectrum (ASD), with suggested rates between 20% and 50% in autistic individuals [2]. Though not uncommon in the general population, there has been a surge in the research looking at the relationship between alexithymia and autism; but how do they interact?

In brief, Alexithymia is:

  • Difficulty identifying emotions 
  • Poor interoception 
  • Difficulty understanding emotions 
  • Trouble with describing emotions 

Alexithymia was a term introduced by Peter Sifneos in the 1970s [3]. Sifneos observed patients who were unable to verbalise their emotions, either through their inability or unawareness of them, or, due to the confusion of emotional and bodily experiences caused by feelings. Individuals who have alexithymic traits usually find it more difficult to identify emotions in others, find it harder to recognise facial expressions, and struggle to interpret voice tones. Perhaps this can partially explain why many autistic individuals find it harder to build connections, as they lack the innate understanding that many people without alexithymia have [4], making it difficult to keep up with the emotional nature of relationships. Alternatively, those ‘on the spectrum’ might struggle to interpret social situations, resulting in the breakdown of relationships. Although this evidence provides a clear indication that Autism and Alexithymia share behavioural characteristics, it fails to explain how they specifically interact with one another. Instead, it merely highlights the importance of both conditions in the traits observed in ASD. 

Other studies have revealed that alexithymia may be associated with impaired interoception. Interoception describes one’s ability to detect and attend to internal bodily sensations [4], such as hunger, thirst, and the need to go to the toilet. This is important to note, because in the past, people have only associated alexithymia with the inability to detect/recognise one’s own emotions, but research into interoception has revealed that alexithymia actually has wide reaching symptomatology. It is also of interest to investigate why impaired interoception is commonly discussed as a “trait” of autism. Given the prevalence of alexithymia in individuals with ASD, could alexithymia be a contributing factor to impaired interoception in autistic individuals? One study suggested that activation of the insula (a cortical region linked with salience detection, self-awareness, interoception, pain processing, and addiction – Papoiu 2016) in autistic individuals is modulated by alexithymic traits, suggesting that alexithymia is in fact the cause of impaired interoception, not ASD [5]. This indicates the potentially important interaction between alexithymia and autism, and how alexithymia may be a cause of some autistic traits (in this case, impaired interoception).   

To contradict this, we can look at evidence that emerged from a 2009 meta analysis.  After studying 24 different papers, it was revealed that the “right anterior (RA) insula is consistently hypoactive in people with ASD” [5,6]. To put this simply, the right anterior insula is thought to be less active in individuals who are ‘on the spectrum’. This specific region of the brain is involved in interoceptive awareness of homeostatic emotions, such as pain, thirst, and hunger, and thus highlights a potential reason as to why impaired interoception exists. The use of a meta-analysis, which is the statistical analysis of multiple results from different papers, adds value to this research finding. Studying numerous papers enables a researcher to draw a more precise result, and could also increase the generalisability, which tends to be less successful in a singular study. As a result, this research evidence can be used to draw the conclusion that there is a consistent hypoactivation of the RA insula in individuals with ASD, which in turn removes the role of alexithymia in the cause of impaired interoception. However, an important question still remains: do all individuals with ASD have impaired interoception? If the answer is no, what else could hypoactivation of the right anterior insula be involved in? From these two studies [above], there may be some association between autism and alexithymia in regards to interoception, however, it is still important to note that many studies contradict this. Thus, further studies into the etiologies and larger/more diverse samples may help elucidate their roles and see if there is an interaction, or if it is simply a coincidence. 

Another study discusses how “alexithymic traits outweigh autistic traits in the explanation of depression in adults with autism” [7], which further illuminates the importance and crossover of alexithymia with ASD comorbidities. Depression is a prevailing comorbidity in ASD, with up to 37% of autistic individuals presenting with depression in their lifetime [7]. This study found that the difficulties in identifying feelings associated with alexithymia is a better predictor of depressive symptoms in autistic individuals than other ASD traits and other alexithymia factors. This emphasises the importance of alexithymia in some of the co-morbidities associated with ASD, and explains why alexithymia may be an important factor to consider in the treatment of individuals with ASD and comorbid depression. Given that alexithymia has a high prevalence in ASD, it raises the question: why is alexithymia higher in individuals with ASD, and is it alexithymia or autism that lead to the traits seen? Furthermore, this could indicate that alexithymia may be a missing link between [some] mental health issues and ASD; highlighting the need for further research to understand the relationship between autism and alexithymia. (Dr Oakley recently wrote an article for Aspiring – to be you regarding Alexithymia and Mental Health : find here)

Though a lot of research has been dedicated to the interaction between alexithymia and ASD, there still is no true understanding of the precise relationship between the two conditions. Could it be that one is of a causal interaction, but if so, in which direction? Alternatively, could it be that one occurs due to the dysfunction caused by the other, or is it just a co-occurrence that is unspecified? Understanding the cognitive and neurophysiological mechanisms of both alexithymia and autism is essential in understanding how the onset of both occur. Maybe their interaction can be explained by the overlap between biological and neurocognitive factors. This potential overlap could explain why autistic people are more likely to display alexithymic traits, as some mechanisms may be similar between the two conditions. Given that ASD is a heterogeneous disorder, and its origins continue to elude scientists, the fundamental relationship between alexithymia and ASD cannot be known. It is therefore vital that researchers conduct further research into the etiology of both conditions so that we can better see if alexithymia causes some ASD traits, the consequence of ASD traits, or neither. Despite these missing links, the studies discussed above have successfully highlighted the importance to consider both conditions when looking at what may be causing the traits shown in an autistic individual. 

When someone asks me how I feel I just go blank, I don’t know how to respond, I try and search for how I feel but I don’t know. Usually I can talk about how I feel when it’s on my terms and once I have processed everything. If I get asked before processing, I get angry and close up. I find people rephrasing ‘how do you feel’ to ‘what are your thoughts’ makes it much easier to suppress the anger. I can then use my brain.

J.S
References
  1. Alexithymia | Autistica. Autistica. 2021 [cited 20 July 2021]. Available from: https://www.autistica.org.uk/what-is-autism/anxiety-and-autism-hub/alexithymia
  2. Poquérusse J, Pastore L, Dellantonio S, Esposito G. Alexithymia and Autism Spectrum Disorder: A Complex Relationship. Front Psychol 2018;9:1196.
  3. Sifneos PE. The prevalence of “alexithymic” characteristics in psychosomatic patients. Psychother Psychosom 1973;22:255–62.
  4. Shah P, Hall R, Catmur C, Bird G. Alexithymia, not autism, is associated with impaired interoception. Cortex 2016;81:215–20.
  5. Hatfield TR, Brown RF, Giummarra MJ, Lenggenhager B. Autism spectrum disorder and interoception: Abnormalities in global integration? Autism 2019;23:212–22.
  6. Martino AD, Di Martino A, Ross K, Uddin LQ, Sklar AB, Xavier Castellanos F, et al. Functional Brain Correlates of Social and Nonsocial Processes in Autism Spectrum Disorders: An Activation Likelihood Estimation Meta-Analysis. Biological Psychiatry 2009;65:63–74.
  7. Bloch C, Burghof L, Lehnhardt F-G, Vogeley K, Falter-Wagner C. Alexithymia traits outweigh autism traits in the explanation of depression in adults with autism. Sci Rep 2021;11:2258.

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