Making the Invisible Visible – On Stress, Sick Leave, and the Need for New Measurement Methods

In its latest newsletter, Hjärnfonden highlights one of the most pressing public health challenges of our time: stress-related ill health. They detail how prolonged stress without recovery affects the brain and list the warning signs that often precede a breakdown.

This issue not only concerns individual suffering but also represents a significant socioeconomic challenge. Looking at national statistics reveals a clear picture of the severity. According to the Swedish Social Insurance Agency's situation assessment, psychiatric diagnoses are currently the single most common reason for sick leave. The figures show that 47.5% of all ongoing sick cases fall into this category. Of these, stress-related mental ill health (e.g., burnout syndrome) accounts for a significant portion – approximately 20.3% of all ongoing sick cases. This means that one in five people who are on sick leave in Sweden today are due to stress.

The statistics also reveal a dramatic gender disparity. Women are significantly overrepresented, making up 79% of the group with stress-related psychological illness. The combination of work life, family responsibilities, and lack of recovery hits hard, particularly affecting women in midlife. We are thus faced with a situation where a large part of the workforce is being incapacitated by conditions that often creep up and are difficult to quantify until it is too late.

When Subjective Symptoms are Not Enough

A challenge with burnout syndrome is its complexity. The course of the illness is rarely linear, and the symptoms – such as memory disturbances, sound sensitivity, and sleep problems – are often diffuse in the early stages. As Hjärnfonden points out, it is crucial to "recognize the signals," but clinical reality shows that it is often difficult to distinguish between normal fatigue and pathological stress based solely on self-assessment.

This is where the need for an expanded diagnostic toolkit becomes apparent. To act preventively, more parameters are needed to help understand what is happening in the body beneath the surface.

NeuroEVs – A Biological Complement

By analyzing neuronal extracellular vesicles (NeuroEVs), biomarkers reflecting communication between cells in the nervous system are studied. It is important to emphasize that an analysis of NeuroEVs is not a definitive solution that can diagnose burnout on its own. Burnout syndrome is a multifaceted diagnosis that requires a combination of clinical assessments, psychosocial situation, and symptomatology. If you are curious about how your own biological NeuroEV profile looks, you can read more here and book your test: About NeuroEVs – analysis of brain-related stress markers in blood samples

However, the method can serve as a valuable complement. In diagnostics that previously relied almost exclusively on conversations and rating scales, NeuroEVs can add:

• Biological Correlation: An opportunity to see if the perceived stress has a measurable counterpart at the cellular level.

  
  

• Early Indication: The potential to detect molecular changes before cognitive symptoms become debilitating.

  
  

• Follow-Up: A method to monitor over time how the body responds to recovery and interventions.

The concept of measuring brain health through blood is gaining strong support in international research. What we are seeing is that prolonged psychosocial stress can affect the blood-brain barrier – the protective wall that normally keeps the brain isolated – causing it to temporarily become more permeable.

Another published study in Frontiers in Public Health (2025) highlights how mental stress and strain among healthcare staff can be linked to measurable changes in specifically blood-based extracellular vesicles. This is also supported by earlier research on emergency physicians, a professional group at high risk of burnout. Raised levels of the protein S100B have been measured in the blood of those with exhaustion symptoms. S100B is a protein usually found within the brain (among other things, in astrocytes), and finding it in the blood is a clear indication that the barrier has yielded to stress.

The conclusion is clear: Stress does not remain in the head – it leaves biological traces that we now have the technology to detect.

The Way Forward

Reducing the number of sick cases requires efforts at all levels. Hjärnfonden's work in disseminating knowledge about the symptoms is fundamental. Developing more methods and tools that make the invisible measurable is equally important and provides both individuals and companies with better conditions for early interventions.