Rethinking Sensory Sensitivities in Autism: The Overlooked Role of Alexithymia

A new twin study published in Translational Psychiatry offers fresh insight into a longstanding question: why do some individuals with autism experience intense sensory sensitivities while others do not? The findings suggest that a trait called alexithymia, which is a difficulty identifying and describing one’s own emotions, may share genetic links with sensory traits often seen in autism. Once alexithymia was taken into account, the previously observed genetic relationship between autism and sensory sensitivities was no longer significant. While these results do not imply that alexithymia causes sensory issues, they raise important questions about how overlapping traits may influence the experiences of autistic individuals and others.

What Is Alexithymia?

Alexithymia is a condition characterized by challenges in recognizing and expressing one’s own emotional states. It is significantly more common in autistic individuals than in the general population but is also found in people with other mental health conditions, including anxiety, depression, and eating disorders. Importantly, alexithymia and autism are distinct—many individuals with autism do not have alexithymia, and vice versa.

Exploring the Genetic Links

Researchers in the United Kingdom analyzed data from 207 twin pairs—both identical and fraternal—from the Twins Early Development Study. The sample included individuals with autism and matched controls. Using gold-standard diagnostic interviews and parent-reported questionnaires, they assessed three key traits:

• Autism-related behaviors
• Sensory sensitivities
• Alexithymia (specifically, difficulty identifying one’s emotions)

Sensory symptoms were measured using the Short Sensory Profile, which examines behaviors such as sensitivity to noise, touch, or visual input. Alexithymia was assessed using a subscale of the Observer Alexithymia Scale, with a focus on emotional insight.

The researchers used bivariate twin modeling to examine the degree to which these traits shared genetic influences.

Key Findings

• All three traits were found to be highly heritable. Autism showed heritability around 82%, alexithymia 84%, and sensory symptoms approximately 57%.
• Autism and sensory symptoms were moderately correlated, with that relationship appearing largely genetic.
• However, when the researchers accounted for alexithymia, the genetic association between autism and sensory symptoms was no longer significant.
• In contrast, the association between alexithymia and sensory sensitivities remained strong—even when autism was controlled for—suggesting these two traits share genetic underpinnings that appear independent of autism.

Understanding Sensory Profiles Through a Broader Lens

The study highlights the possibility that sensory sensitivities may be influenced by emotional insight and interoceptive processing, which are central features of alexithymia.

The researchers discuss two ways these differences may present:

• Hypersensitivity, where external input like noise or touch feels overly intense or even painful.
• Hyposensitivity, where a person may be less aware of or responsive to sensory stimuli.

Both of these patterns may relate to how an individual interprets and processes internal body cues—a function that can differ significantly in people with alexithymia.

Why It Matters

This research raises the possibility that sensory sensitivities often attributed to autism may instead be influenced by overlapping but distinct traits. If so, this has several important implications:

• Assessment: Professionals might benefit from evaluating emotional awareness and interoception, in addition to traditional sensory profiles.
• Support: Intervention strategies that include emotion identification and interoceptive awareness may complement sensory-based therapies.
• Diagnosis: A more nuanced understanding of co-occurring traits like alexithymia can lead to more individualized support and prevent assumptions about which features are truly part of autism.

Limitations to Keep in Mind

While the findings are compelling, they come with limitations:

• Parent-report tools may introduce bias, especially when one parent completes assessments for both twins.
• Only one component of alexithymia (difficulty identifying emotions) was studied.
• The study could not fully test whether alexithymia’s genetic influence on autism would similarly affect its link to sensory symptoms.

These results are not definitive and do not suggest that alexithymia alone accounts for all sensory experiences. Rather, they point to the importance of considering how multiple traits may interact genetically and developmentally.

A More Complete Picture

This study contributes to a growing body of research suggesting that traits often seen together, such as autism, alexithymia, and sensory sensitivities, may be influenced by shared, but distinct, biological factors. Recognizing these overlaps can help therapists, educators, and caregivers provide more personalized and effective support for each child. Understanding how alexithymia and sensory processing interact may also inform approaches across other diagnoses, such as ADHD or anxiety, where sensory sensitivities are also common.

Reference:

Yorke, I., Murphy, J., Rijsdijk, F., Colvert, E., Lietz, S., Happé, F., & Bird, G. (2025). Alexithymia may explain the genetic relationship between autism and sensory sensitivity. Translational psychiatry, 15(1), 75.

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