We've written before about how allostatic overload has been linked to changes in the body. This piece looks at some of the most direct evidence of that: what chronic occupational stress does to the physical structure of the brain, and whether it stays that way.
The study that made this concrete
A 2018 study in Cerebral Cortex gave 48 patients diagnosed with occupational Exhaustion Syndrome, a clinical diagnosis used in Sweden for severe exhaustion caused by long-term stress, structural MRI scans, alongside 80 healthy controls. All patients had been on sick leave for stress symptoms for at least three months, and reported working 60 to 70 hours a week for several years beforehand.
The scans found differences from the healthy controls: thinner cortex in the prefrontal cortex and superior temporal gyrus, an enlarged amygdala, and a smaller caudate. All of these differences were related to how much stress people reported, and prefrontal thickness also correlated with a reduced ability to regulate negative emotion, a struggle many people with burnout will recognise.
The part most coverage of this leaves out
Forty-four of the original participants, 25 patients and 19 controls, came back for a second scan one to two years later. The returning patients had gone through a 3-month stress rehabilitation programme in the meantime, group cognitive therapy combined with physical therapy focused on breathing and relaxation. By that second scan, 70% of patients were back working full-time.
What changed, and what came back
Structural findings in patients with occupational exhaustion syndrome at intake (48 patients) and at a second scan one to two years later (25 patients, all of whom had taken part in a 3-month rehabilitation programme).
Source: Savic, Perski & Osika, Cerebral Cortex, 2018. "Normalised" is the study's own term for these changes at follow-up.
Two things stand out in that table. First, the prefrontal thinning, the change most closely tied to emotional regulation, had normalised by the second scan. The study had no untreated comparison group, so it can't say how much of that was down to the programme and how much to time and reduced stress. Second, not everything did. The enlarged amygdala and the thinner temporal cortex stayed as they were, even as patients recovered functionally and their stress scores dropped. Recovery here wasn't all-or-nothing, and it wasn't uniform.
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This isn't unique to burnout
Cortical thinning shows up across several stress-related conditions, not just occupational burnout. A small 2012 study comparing 10 mining-disaster survivors with recent-onset PTSD against 10 survivors without PTSD found thinning in different regions, the left parietal lobe, right inferior frontal gyrus and right parahippocampal gyrus, and thickness in the inferior frontal gyrus was linked to symptom severity. A 2025 study comparing 30 people with depression and chronic stress against 30 people with depression alone found the chronic-stress group had more thinning, and relapsed sooner after treatment: at 5.4 months on average, against 8.3 months.
The consistent thread is that chronic stress is associated with changes in brain structure across more than one condition, though these studies can't prove the stress alone caused them. Where people were scanned again, some of the change had recovered: in the exhaustion syndrome study, prefrontal thickness normalised, and in the 2025 depression study, cortical thickness improved with treatment, though it didn't fully reach healthy levels. The PTSD study scanned people only once, so it can't speak to recovery.
What this means for you
The honest, defensible takeaway is this: if chronic stress has left you feeling like your focus, memory, or emotional steadiness isn't what it used to be, that's worth taking seriously, and it isn't necessarily permanent either. In the same study, some of the brain differences, including in the prefrontal region tied to emotional regulation, had returned to normal by the second scan, though others had not, and there was no untreated group to compare with.
That's not a reason to panic about a stressful season. It's a reason to take a long, overloaded one seriously, and to talk it through with a GP if it's affecting you.
Sources
Savic I, Perski A, Osika W (2018). "MRI Shows that Exhaustion Syndrome Due to Chronic Occupational Stress is Associated with Partially Reversible Cerebral Changes." Cerebral Cortex, 28(3):894-906, peer reviewed. Liu Y, Li YJ, Luo EP, Lu HB, Yin H (2012). "Cortical Thinning in Patients with Recent Onset Post-Traumatic Stress Disorder after a Single Prolonged Trauma Exposure." PLOS ONE, 7(6):e39025, peer reviewed. Li et al. (2025). "The impact of chronic stress on cortical thickness in patients with depression." Frontiers in Psychiatry, 16:1554476, peer reviewed.
Start with a baseline
The Stress Biomarker Checklist
A 13-page evidence review covering six biomarker systems, a reflective self-check, and what the research does and doesn’t show about each. Free.
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The Capio Initiative is an educational platform, not a medical practice. The biomarkers discussed here help explain stress physiology. None of them can diagnose burnout, and we never use them to diagnose anything. Speak with a qualified healthcare professional before changing anything about your recovery or your use of tracking devices.
