Long-Term Occupational Stress Is Associated with Regional Reductions in Brain Tissue Volumes

Summary & key facts

Several brain-imaging studies found that people with long-term work-related burnout showed differences in brain structure and function compared with matched healthy adults. In groups where participants had worked more than about 60–70 hours per week for several years, researchers reported larger amygdala size, thinner medial prefrontal cortex (mPFC) tissue, weaker connections between the amygdala and emotion-regulating brain areas (ACC and mPFC), stronger startle reactions when asked to calm their emotions, and other regional volume changes. These results are associations from modest-sized samples and do not prove that work stress causes the brain changes.

Key facts:

• One study tested 40 people with diagnosed burnout (each reporting >60–70 work hours per week for several years) and 70 matched healthy controls using emotion-regulation tasks and resting-state fMRI.
• When asked to down-regulate negative emotions, the burnout group showed bigger physical startle reactions than controls, indicating more difficulty calming strong negative responses.
• The burnout group had relatively larger amygdalae and weaker functional connectivity between the amygdala and the anterior cingulate cortex (ACC) and between the amygdala and medial prefrontal cortex (mPFC).
• A separate study compared 40 burnout patients to 40 healthy controls using MRI and the Maslach Burnout Inventory; it found thinner cortex in the mPFC and larger amygdalae in the burnout group.
• Researchers also reported shrinkage in the caudate that correlated with participants’ reports of workplace stress in the anatomical study.
• Authors of the studies describe these findings as correlations and offer theories about overactivation cycles between the amygdala and mPFC, but the studies do not establish that work stress causes the brain changes and have modest sample s

Abstract

There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM) and white matter (WM) volumes, and the volumes of hippocampus, caudate, and putamen - structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment.

Topics

Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes Functional Brain Connectivity Studies Stress Responses and Cortisol

Categories

Behavioral Neuroscience Life Sciences Neuroscience

Tags

Anterior cingulate cortex Chronic stress Cognition Dorsolateral prefrontal cortex Grey matter Hippocampus Magnetic resonance imaging Medicine Neuroscience Prefrontal cortex Psychology Putamen Radiology Voxel Voxel-based morphometry White matter