Alexithymia—a condition associated with difficulty in identifying and describing one’s own emotions—may be a strong influence in how much sensory sensitivity people with autism spectrum disorder experience, reports a study in Translational Psychiatry.
“Reported across almost all sensory domains (e.g., taste, touch, audition, smell, vision and interoception), atypical sensory experience is now considered a diagnostic feature of autism … and ranks as one of the top concerns reported by autistic individuals,” wrote Isabel Yorke, Ph.D., of King’s College London, and colleagues. “Given the impact of sensory sensitivity on the wellbeing of autistic individuals, understanding the aetiological factors that contribute towards atypical sensory experience is an urgent research goal.”
Yorke and colleagues made use of the Twins Early Development Study, an ongoing cohort study that recruited more than 16,000 pairs of twins born in England or Wales between 1994 and 1996. They included data from 127 twin pairs who had received comprehensive diagnostic assessments and in which at least one twin had autism. The researchers then added in 80 families in which neither twin had autism. The final sample included 55 identical twins and 152 fraternal twins.
The researchers conducted a series of modeling analyses to examine the interaction between the severity of alexithymia, sensory issues, and/or autism in the twins. The co-occurrences of these conditions in identical versus fraternal twins was also compared to explore the role of genetics versus environment.
Overall, the analysis found a strong correlation between autism and sensory symptoms; however, after controlling for alexithymia, the association between autism and sensory symptoms was no longer significant. In contrast, the correlation between alexithymia and sensory symptoms was significant, even after factoring in the influence of autism.
“This suggests that alexithymia and sensory processing share genetic factors, independent of those that increase the likelihood of autism,” Yorke and colleagues wrote. “As such, although alexithymia and sensory symptoms commonly co-occur with autism (potentially due to a degree of shared genetic liability), they are also independent from autism.”
Given that sensory symptoms are now included in the diagnostic criteria for autism spectrum disorder, “these results suggest a need to consider the influence of alexithymia both when diagnosing autism and providing support,” they concluded.
For related information, see the Journal of Neuropsychiatry and Clinical Neurosciences article “Frontotemporal Dementia: A Window to Alexithymia.”
(Image: Getty Images/iStock/globalmoments)
Don't miss out! To learn about newly posted articles in Psychiatric News, please sign up here.