Occupational stress is associated with sex and subregion specific modifications of the amygdala volumes

Abstract

Background: Despite the rapid increase in reports of exhaustion syndrome (ES) due to daily occupational stress, the mechanisms underlying ES are unknown. In the present study, we investigated whether occupational ES is associated with specific modifications of the subfields of the amygdala and hippocampus resembling those described in other chronic stress conditions. Special focus was paid to possible sex differences.

Methods: As a follow up to our previous studies of occupational ES, we carried out MRI-based subfield segmentation of the hippocampus and amygdala volumes in 58 patients with occupational ES (22 males) and 65 age-matched controls (27 males) (age range 30–46 years).

Results: There was a significant and bilateral enlargement of the lateral, basal and central nucleus of the amygdala in patients with ES (corrected for the total intracranial volume (ICV)). These differences were detected only in females. Higher values in the right central and right basal amygdala remained when the whole amygdala volume was used as reference, instead of the ICV. Notably, in female patients the volumes of these specific nuclei were positively correlated with the degree of perceived stress. No changes in the hippocampus subfields were detected in female or male patients.

Conclusions: The findings underline that ES is a chronic stress condition, suggesting that not only extreme forms of stress, but also the everyday stress is associated with localized differences from controls in the amygdala. The absence of significant alterations among men with ES despite a similar degree of perceived stress supports the notion that women seem more susceptible to stress-related cerebral changes, and may explain the higher prevalence of ES among women.

Keywords:

• Exhaustion syndrome
• MRI
• Hippocampus subfields
• Amygdala subfields
• Chronic stress
• Occupational stress

Acknowledgements

We acknowledge the stress clinic, Sabbatsberg in Stockholm for referral of ES patients. We are especially indebted to Dr Vassiliki Perris for recruiting several of the patients, and Christos Saripanidis for recruiting control subjects.

Declaration of interest

None of the authors has any conflict of interest to disclose.

Additional information

Funding

This study was supported by AFA Försäkring and Forskningsrådet för Hälsa, Arbetsliv och Valfärd (FORTE).