Measuring alexithymia in autistic individuals | Spectrum
Katherine Gotham
Assistant Professor of Psychiatry, Rowan University
Zachary J. Williams
MD / Ph.D. college student, Vanderbilt University
People differ greatly in their ability to identify and describe the emotions they feel every day. While many people can easily tell whether they are happy, sad, angry, or scared, others have great difficulty understanding or describing their emotional states to others. People with such challenges should have a high degree of “alexithymia”,“A personality trait that literally means“ no words for emotions ”. In addition to having trouble identifying and describing feelings, people with high alexithymia prefer to focus their thoughts on things they can see or touch rather than on their own emotional experiences or those of others, a cognitive style called as “externally oriented thinking” is called.
Many people on the autism spectrum are familiar with alexithymia, even if they haven’t heard the term. Studies estimate that nearly half of autistic adults exceed clinical limits for “high alexithymia,” compared to just 5 to 10 percent of the general population. In autistic people, higher levels of alexithymia predict more significant social communication difficulties, as well as psychological problems such as anxiety. Additionally, research suggests that certain traits commonly associated with autism (such as differences in empathy and difficulty recognizing emotional facial expressions) may be due to alexithymia rather than autism itself.
Despite the growing interest in alexithymia in autism research, few studies have investigated whether the tools commonly used to measure this trait work reliably in autistic populations. Even the most popular metric, the 20-element Toronto Alexithymia Scale (TAS-20), is routinely used, although researchers don’t know if it measures the same underlying construct in autistic and non-autistic people. Without this information, we cannot be sure that the differences in scores on the TAS-20 or other measures reflect real differences in alexithymia, rather than differences in the interpretation of questionnaires between autistic and non-autistic people.
To fill this gap, our team conducted the first large-scale validation study of the TAS-20 on a sample of autistic adults. We found that many of his questions were poor indicators of alexithymia in autistic adults, which prompted us to develop a new method of assessment, the general alexithymia factor score, or GAFS-8. Due to a copyright problem, we could not name our new method after the TAS-20 instrument, as we did in a first, withdrawn version of our work. But the GAFS-8 score is based on eight of the TAS-20 questions that seem to work well for both autistic and non-autistic individuals. Our research also questions the extent to which alexithymia is related to certain mental health problems in people on the autism spectrum.
Eight is enough:
For our study, published in Molecular Autism this month, we used the SPARK participant pool to recruit a sample of 743 verbally fluent autistic adults. (SPARK is funded by the Simons Foundation, Spectrum’s parent organization.) Participants, ages 18 to 45, all completed a series of questionnaires, including the TAS-20. This large data set enabled us to use statistical models that estimate the degree to which the degree of alexithymia in autistic adults accounted for their results on each of the 20 questions.
The TAS-20 has three sub-scales: sets of questions that measure difficulty in identifying emotions, difficulty in describing emotions, and externally oriented thinking. We found little support for articles rating this last category. Questions such as “I prefer to analyze problems rather than just describe them” and “Being in touch with emotions is important” did not correlate well with model-based estimates of “general alexithymia” in our sample of autistic adults. These questions and a few others seemed to add little more than measurement errors.
This discovery prompted our efforts to identify a subset of eight TAS-20 questions that can reliably assess alexithymia in individuals with the autism spectrum. Using statistical methods, we validated the GAFS-8 score in both autistic and non-autistic adults and provided the first evidence of an alexithymia score that measures the same underlying construct in both populations.
We also examined correlations between GAFS-8 scores and other traits of interest, such as autistic traits, quality of life, and mental health problems such as depression and anxiety. As expected, the GAFS-8 score correlated positively with autistic features and psychological problems and also predicted a reduced quality of life.
We went a step further and examined these correlations by considering the level of neuroticism, or the extent to which a person experiences stress and negative moods in their daily life. Unlike some other alexithymia measures, the TAS-20 measures both alexithymia and neuroticism, according to a 2020 paper, making it difficult to know which of the two personality traits is contributing to the outcomes of interest.
When we statistically controlled neuroticism in our SPARK sample, we found that alexithymia, as measured by GAFS-8, still strongly predicted autistic traits and quality of life, but the associations between GAFS-8 scores and mental health symptoms became much lower and were no longer meaningful in some cases. More research is needed to determine whether alexithymia actually predicts the development of mental health problems in autistic adults, or whether co-occurring neuroticism – an established predictor of poor mental health – is responsible.
To facilitate the use of the GAFS-8 in research and clinical practice, we have created a free and easy-to-use online score calculator. It enables the calculation of population-normalized GAFS-8 scores as well as individual score reports that classify a particular person as “high alexithymia” or not. We hope that this measure can replace the TAS-20 total scores in studies comparing alexithymia in autistic and non-autistic groups.
Since the GAFS-8 is confused by neuroticism and no items are missing to evaluate the area of “externally oriented thinking” of alexithymia, alternative measures such as the Perth Alexithymia Questionnaire and the Toronto Structured Interview for Alexithymia may be more suitable for use in autistic people prove. although research is needed to validate these tools in this group. In addition, since our SPARK sample was disproportionately white, female, well educated, and diagnosed with autism in adulthood, it would also be valuable to test the GAFS-8 in autistic people with different demographics.
Our study is part of a broader movement to determine whether widespread psychological tools are working effectively in people with autism, or whether new or redesigned tools are needed. For example, in other recent work we have shown that the Beck Depression Inventory-II is a valid measure of self-reported depressive symptoms in autistic adults. In contrast, in the case of anxiety in children, other researchers found that children on the spectrum needed a reassessment. We hope that by highlighting the importance of developing and validating measurements, we can inspire other autism researchers to join this process and critically examine the measurement tools on which our science is built.
Quote this article: https://doi.org/10.53053/FWEH2679
