Why sensitivity and stress cut across diagnoses — and what the Biomarker Workshop in December sets out to examine

In a portrait published recently in a Swiss online magazine, a young woman describes her everyday life with autism. She almost always wears headphones. Not to listen to music — but to turn the noise down far enough for work to become possible.

Anyone reading this sees an aid. Anyone looking more closely sees a calculation.

The headphones are not a quirk and not an accessory. They are the visible end of a calculation that either works out or does not, every single day: how much arrives unfiltered, how much effort it takes to function anyway, and is there enough left in the evening to start again from zero the next morning? People with very different diagnoses make this calculation — and some with no diagnosis at all.

This is exactly what the Biomarker Workshop on 10 December in Zurich is about.

Two dimensions that appear in no diagnostic manual

The diagnoses of ADHD, autism spectrum disorder and post-traumatic stress disorder have different histories, different guidelines and different treatment pathways. What connects them again and again in the consulting room, however, are two descriptions that cut across them.

The first is sensitivity: how much of the environment arrives unfiltered. Light that is too bright. Sounds that do not fade into the background. And the less often noticed flip side — stimuli that do not arrive at all, pain that is noticed late.

The second is stress: not the single stressful event, but whether the load drops back in between. Where it does not, the next day starts a little higher, and at some point a trifle is enough for something to tip over. From the outside this looks like a wildly excessive overreaction. It is the sum of the day, made visible at its last point.

Neither description is a diagnosis. Both are characteristics that every person has — to very different degrees. And this is the point that carries the workshop question: Two people with the same diagnosis can be further apart on these two dimensions than two people with different diagnoses.

So knowing the category does not yet tell you what you are dealing with.

Why this is not an academic dispute

For treatment it makes a considerable difference whether someone carries a high sensory load with good capacity for recovery or a moderate sensory load with no recovery at all. In the first case, whatever dampens the individual stimulus helps. In the second it does not — there, recovery has to be built into the day, otherwise any dampening of stimuli merely postpones the problem.

Categorical diagnostics cannot provide this distinction. It answers a yes-or-no question and is silent on everything that has to be decided afterwards. This is no criticism of the guidelines: a diagnosis is the prerequisite for many things — for cost approvals, for school measures, for access to treatment. It is just not a treatment plan.

That sensory sensitivity and psychological strain are closely linked is one of the more stable findings in this field; a meta-analysis of 64 studies found medium to large associations between over-responsivity and anxiety and depression, and considerably weaker ones for reduced sensitivity (Chen et al. 2024). What does not follow from this is the direction: whether sensitivity produces anxiety, anxiety sharpens perception, or both reinforce each other cannot be decided from cross-sectional data.

Another, very practical connection is well supported: predictability. In a study of 64 autistic and 85 typically developing children, intolerance of uncertainty and anxiety together explained around half of the differences in sensory sensitivity among the autistic children — among the typically developing children it was less than one fifth (Neil et al. 2016). Announced noise is different noise from unannounced noise.

What can be measured — and what cannot yet

This is where the work begins to which a foundation like ours can contribute. If sensitivity and stress are the two dimensions on which people differ, the question arises whether they can be measured rather than merely asked about.

The honest interim assessment: partly, and not where people looked first. A systematic review of 31 studies on cortisol in autism found an inconsistent picture — elevated, blunted and unremarkable stress responses side by side. What is notable is a secondary finding: the subjectively reported stress level was considerably higher than was reflected in the biological measures (van der Linden et al. 2022). Either cortisol is the wrong measure for this kind of constant strain, or the groups studied were too heterogeneous to show a signal. Both argue for measuring closer to the processing itself rather than to its hormonal consequence.

One pointer in this direction comes from our work with the University of Skopje: the EEG channels that contributed most to distinguishing autistic from typically developing children were those over areas of visual processing (Tenev et al. 2025). This is a hint towards the sensory side — and explicitly not evidence that the chain of strain described here can be mapped in the EEG. The two questions lie side by side; they are not the same.

What is up for discussion on 10 December

The Biomarker Workshop 2026 deliberately places ADHD, autism and PTSD side by side and asks what remains when the categories are set aside for a moment and one describes instead how sensitive a system is and how it regulates itself. The keynote will be given by Tony Attwood and Michelle Garnett.

This does not abolish the diagnosis. It is an attempt to place something alongside it that the diagnosis cannot provide: a description of the individual person that is measurable and repeatable.

And, back to the beginning, it is an attempt to read the headphones correctly. Not as an abnormality to be treated away, but as information about how much this person is carrying right now.

What this text does not show

That sensitivity and stress can be described as two dimensions cutting across diagnoses is a viable working model — not a proven mechanism. That the phenomena overlap does not mean they share the same cause; it may equally be that different paths lead to a similar presentation.

For neither dimension is there currently a measure that carries diagnostic weight in the individual case. What exists are group differences with overlapping distributions — and the task of turning them into something that applies to a single person. That very step is still outstanding.

Sources

• Chen, Y. et al. (2024): A systematic review and meta-analysis of the relationship between sensory processing differences and internalising/externalising problems in autism. Clinical Psychology Review. DOI 10.1016/j.cpr.2024.102516
• Neil, L.; Choque Olsson, N.; Pellicano, E. (2016): The Relationship Between Intolerance of Uncertainty, Sensory Sensitivities, and Anxiety in Autistic and Typically Developing Children. Journal of Autism and Developmental Disorders. DOI 10.1007/s10803-016-2721-9
• Tenev, A.; Markovska-Simoska, S.; Müller, A.; Mishkovski, I. (2025): Entropy and Complexity in QEEG Reveal Visual Processing Signatures in Autism. Brain Sciences 15(9), 951.
• van der Linden, K.; Simons, C.; van Amelsvoort, T.; Marcelis, M. (2022): Emotional stress, cortisol response, and cortisol rhythm in autism spectrum disorders: A systematic review. Research in Autism Spectrum Disorders 98, 102039. DOI 10.1016/j.rasd.2022.102039