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Burnout is associated with constant stress experienced by individuals in high demanding positions. There is currently no single agreed-upon definition for burnout, however common symptoms such as chronic stress manifest in populations who regularly engage in physically/mentally taxing activities without access to sufficient recovery periods. Even though negative experiences increase the anxiety level in everyone, individuals with chronic stress are more prone to develop severe mood dysregulation and other symptoms in response to anxiety [1]. The ability to perceive and process information is also jeopardized under constant stress [2,3]. COVID-19 outbreak has brought forth a slew of challenges that threatened the economic status, access to social support, and workflow/lifestyle practices for millions worldwide. The significant changes in our lifestyle due to this pandemic have increased stress levels globally [4,5]. Chronic stress experienced by individuals can eventually lead to manifestations of symptoms similar to burnout if left untreated.
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Signs of burnout:
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Critical neural circuits involved in processing cognition and emotion are heavily impacted by chronic stress. The limbic system, which comprises several sub-structures such as the amygdala and hippocampus, is involved in processing/regulating emotions and memory. The prefrontal cortex (PFC) is involved in processing cognition, self/social awareness, and risk assessment and decision-making. The elaborate bidirectional communication between the limbic system and PFC allows to effectively perceive, memorize, and respond to stimuli. Chronic stress has been associated with disrupting the processes in these regions through structural, neurochemical, and neuroendocrinological changes [6]. Hormone such as glucocorticoids has been observed to be involved in the structural remodeling of neurons in the amygdala, hippocampus, and PFC in response to stress [7].
In the hippocampus, chronic stress has been linked to shrinkage and debranching of dendrites of the dentate gyrus (DG) and CA3 neurons and loss of dendritic spines in CA1 neurons. Reduced neurogenesis in DG has also been associated with chronic stress [6]. DG, CA3, and CA1 neurons form the tri-synaptic circuit inside the hippocampus, which is involved in processing memory, especially in the context of space and time. Hippocampus also has an important role in mood regulation. For example, antidepressants can increase neurogenesis in DG, which is normally regulated by the adrenal steroid. Loss of volume in DG has been observed in individuals suffering from mood dysregulations (depression) and stress [8].
Unlike CA3 neurons in the hippocampus, the amygdala can increase dendritic branching and density. When experiencing chronic stress, brain-derived neurotrophic factor (BDNF), which promotes growth, maturation, and maintenance of neurons, are overexpressed in the basolateral amygdala (BLA) while downregulated in CA3 neurons [9]. Amygdala overactivity, which can be associated with its increased synaptic density, disrupts mood regulation and increases sensitivity to anxiety. However, it is important to note that amygdala volume is not related to the severity of stress and depressive symptoms [10].
Chronic stress can also lead to an array of hormonal and protein expression dysregulations, ultimately altering the neural architecture in PFC. Cognitive flexibility, planning, impulse control, and decision-making are all examples associated with PFC. Chronic stress can disrupt many of these processes as a result [11]. Although stress can change the dendritic modeling in these regions, it is crucial to consider the plastic nature of the brain. Most structural changes that occurred due to environmental stressors are reversible or preventable by adapting certain activities. Meditation, exercise, proper nutrition, a good sleep hygiene, and socialization (although limited due to the pandemic) can help to reduce the symptoms derived from stress.
In the hippocampus, chronic stress has been linked to shrinkage and debranching of dendrites of the dentate gyrus (DG) and CA3 neurons and loss of dendritic spines in CA1 neurons. Reduced neurogenesis in DG has also been associated with chronic stress [6]. DG, CA3, and CA1 neurons form the tri-synaptic circuit inside the hippocampus, which is involved in processing memory, especially in the context of space and time. Hippocampus also has an important role in mood regulation. For example, antidepressants can increase neurogenesis in DG, which is normally regulated by the adrenal steroid. Loss of volume in DG has been observed in individuals suffering from mood dysregulations (depression) and stress [8].
Unlike CA3 neurons in the hippocampus, the amygdala can increase dendritic branching and density. When experiencing chronic stress, brain-derived neurotrophic factor (BDNF), which promotes growth, maturation, and maintenance of neurons, are overexpressed in the basolateral amygdala (BLA) while downregulated in CA3 neurons [9]. Amygdala overactivity, which can be associated with its increased synaptic density, disrupts mood regulation and increases sensitivity to anxiety. However, it is important to note that amygdala volume is not related to the severity of stress and depressive symptoms [10].
Chronic stress can also lead to an array of hormonal and protein expression dysregulations, ultimately altering the neural architecture in PFC. Cognitive flexibility, planning, impulse control, and decision-making are all examples associated with PFC. Chronic stress can disrupt many of these processes as a result [11]. Although stress can change the dendritic modeling in these regions, it is crucial to consider the plastic nature of the brain. Most structural changes that occurred due to environmental stressors are reversible or preventable by adapting certain activities. Meditation, exercise, proper nutrition, a good sleep hygiene, and socialization (although limited due to the pandemic) can help to reduce the symptoms derived from stress.
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More and more research every year is presented on the utility of mindfulness meditation to reduce stress levels. The effect of mindfulness on brain circuitry is not yet fully understood [12]. Since the practice requires active control of attention, it is no surprise that attention control regions such as the anterior cingulate cortex and striatum are involved. Similar to exercising the muscles, the practice of meditation promises to strengthen control over attention and emotion over time.
Resources for mediation: https://www.mindful.org/how-to-meditate/#why https://www.headspace.com/stress Sleep plays a crucial role in cognitive functions such as memory and emotional processing. Lack of sleep has been associated with increased levels of anxiety, poor memory, and emotional dysregulation [13]. A recent study found that sleep quality among students has been worse than workers [14]. This could be due to the drastic transformation in learning/teaching habits students had to face during the lockdowns. Individuals involved in highly stressful occupations must be frequently reminded of their health by proactively engage in activities that reduce mental stress. This blog has addressed how stress can impact cognition while providing solutions to minimize the impact.
With the current pandemic restrictions in place, if mental health awareness is not properly advocated, individuals with a lack of access to resources and support can suffer cognitive decline. A healthy society requires healthy individuals with healthy minds. |
Coping with stress (CDC)
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References:
1) Lupien, S. J., Maheu, F., Tu, M., Fiocco, A., & Schramek, T. E. (2007). The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition. Brain and cognition, 65(3), 209–237. https://doi.org/10.1016/j.bandc.2007.02.007
2) Yuen, E. Y., Wei, J., Liu, W., Zhong, P., Li, X., & Yan, Z. (2012). Repeated stress causes cognitive impairment by suppressing glutamate receptor expression and function in prefrontal cortex. Neuron, 73(5), 962–977. https://doi.org/10.1016/j.neuron.2011.12.033
3) Marin, M. F., Lord, C., Andrews, J., Juster, R. P., Sindi, S., Arsenault-Lapierre, G., Fiocco, A. J., & Lupien, S. J. (2011). Chronic stress, cognitive functioning and mental health. Neurobiology of learning and memory, 96(4), 583–595. https://doi.org/10.1016/j.nlm.2011.02.016
4) Park, C. L., Russell, B. S., Fendrich, M., Finkelstein-Fox, L., Hutchison, M., & Becker, J. (2020). Americans' COVID-19 Stress, Coping, and Adherence to CDC Guidelines. Journal of general internal medicine, 35(8), 2296–2303. https://doi.org/10.1007/s11606-020-05898-9
5) Chew, N., Lee, G., Tan, B., Jing, M., Goh, Y., Ngiam, N., Yeo, L., Ahmad, A., Ahmed Khan, F., Napolean Shanmugam, G., Sharma, A. K., Komalkumar, R. N., Meenakshi, P. V., Shah, K., Patel, B., Chan, B., Sunny, S., Chandra, B., Ong, J., Paliwal, P. R., … Sharma, V. K. (2020). A multinational, multicentre study on the psychological outcomes and associated physical symptoms amongst healthcare workers during COVID-19 outbreak. Brain, behavior, and immunity, 88, 559–565. https://doi.org/10.1016/j.bbi.2020.04.049
6) McEwen, B. S., Nasca, C., & Gray, J. D. (2016). Stress Effects on Neuronal Structure: Hippocampus, Amygdala, and Prefrontal Cortex. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 41(1), 3–23. https://doi.org/10.1038/npp.2015.171
7) Popoli, M., Yan, Z., McEwen, B. S., & Sanacora, G. (2011). The stressed synapse: the impact of stress and glucocorticoids on glutamate transmission. Nature reviews. Neuroscience, 13(1), 22–37. https://doi.org/10.1038/nrn3138
8) Taupin P. (2006). Neurogenesis and the effect of antidepressants. Drug target insights, 1, 13–17
9) Govindarajan, A., Rao, B. S., Nair, D., Trinh, M., Mawjee, N., Tonegawa, S., & Chattarji, S. (2006). Transgenic brain-derived neurotrophic factor expression causes both anxiogenic and antidepressant effects. Proceedings of the National Academy of Sciences of the United States of America, 103(35), 13208–13213. https://doi.org/10.1073/pnas.0605180103
10) Morey, R. A., Gold, A. L., LaBar, K. S., Beall, S. K., Brown, V. M., Haswell, C. C., Nasser, J. D., Wagner, H. R., McCarthy, G., & Mid-Atlantic MIRECC Workgroup (2012). Amygdala volume changes in posttraumatic stress disorder in a large case-controlled veterans group. Archives of general psychiatry, 69(11), 1169–1178. https://doi.org/10.1001/archgenpsychiatry.2012.50
11) Arnsten A. F. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature reviews. Neuroscience, 10(6), 410–422. https://doi.org/10.1038/nrn2648
12) Tang, Y. Y., Hölzel, B. K., & Posner, M. I. (2015). The neuroscience of mindfulness meditation. Nature reviews. Neuroscience, 16(4), 213–225. https://doi.org/10.1038/nrn3916
13) Abel, T., Havekes, R., Saletin, J. M., & Walker, M. P. (2013). Sleep, plasticity and memory from molecules to whole-brain networks. Current biology : CB, 23(17), R774–R788. https://doi.org/10.1016/j.cub.2013.07.025
14) Marelli, S., Castelnuovo, A., Somma, A., Castronovo, V., Mombelli, S., Bottoni, D., Leitner, C., Fossati, A., & Ferini-Strambi, L. (2021). Impact of COVID-19 lockdown on sleep quality in university students and administration staff. Journal of neurology, 268(1), 8–15. https://doi.org/10.1007/s00415-020-10056-6
1) Lupien, S. J., Maheu, F., Tu, M., Fiocco, A., & Schramek, T. E. (2007). The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition. Brain and cognition, 65(3), 209–237. https://doi.org/10.1016/j.bandc.2007.02.007
2) Yuen, E. Y., Wei, J., Liu, W., Zhong, P., Li, X., & Yan, Z. (2012). Repeated stress causes cognitive impairment by suppressing glutamate receptor expression and function in prefrontal cortex. Neuron, 73(5), 962–977. https://doi.org/10.1016/j.neuron.2011.12.033
3) Marin, M. F., Lord, C., Andrews, J., Juster, R. P., Sindi, S., Arsenault-Lapierre, G., Fiocco, A. J., & Lupien, S. J. (2011). Chronic stress, cognitive functioning and mental health. Neurobiology of learning and memory, 96(4), 583–595. https://doi.org/10.1016/j.nlm.2011.02.016
4) Park, C. L., Russell, B. S., Fendrich, M., Finkelstein-Fox, L., Hutchison, M., & Becker, J. (2020). Americans' COVID-19 Stress, Coping, and Adherence to CDC Guidelines. Journal of general internal medicine, 35(8), 2296–2303. https://doi.org/10.1007/s11606-020-05898-9
5) Chew, N., Lee, G., Tan, B., Jing, M., Goh, Y., Ngiam, N., Yeo, L., Ahmad, A., Ahmed Khan, F., Napolean Shanmugam, G., Sharma, A. K., Komalkumar, R. N., Meenakshi, P. V., Shah, K., Patel, B., Chan, B., Sunny, S., Chandra, B., Ong, J., Paliwal, P. R., … Sharma, V. K. (2020). A multinational, multicentre study on the psychological outcomes and associated physical symptoms amongst healthcare workers during COVID-19 outbreak. Brain, behavior, and immunity, 88, 559–565. https://doi.org/10.1016/j.bbi.2020.04.049
6) McEwen, B. S., Nasca, C., & Gray, J. D. (2016). Stress Effects on Neuronal Structure: Hippocampus, Amygdala, and Prefrontal Cortex. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 41(1), 3–23. https://doi.org/10.1038/npp.2015.171
7) Popoli, M., Yan, Z., McEwen, B. S., & Sanacora, G. (2011). The stressed synapse: the impact of stress and glucocorticoids on glutamate transmission. Nature reviews. Neuroscience, 13(1), 22–37. https://doi.org/10.1038/nrn3138
8) Taupin P. (2006). Neurogenesis and the effect of antidepressants. Drug target insights, 1, 13–17
9) Govindarajan, A., Rao, B. S., Nair, D., Trinh, M., Mawjee, N., Tonegawa, S., & Chattarji, S. (2006). Transgenic brain-derived neurotrophic factor expression causes both anxiogenic and antidepressant effects. Proceedings of the National Academy of Sciences of the United States of America, 103(35), 13208–13213. https://doi.org/10.1073/pnas.0605180103
10) Morey, R. A., Gold, A. L., LaBar, K. S., Beall, S. K., Brown, V. M., Haswell, C. C., Nasser, J. D., Wagner, H. R., McCarthy, G., & Mid-Atlantic MIRECC Workgroup (2012). Amygdala volume changes in posttraumatic stress disorder in a large case-controlled veterans group. Archives of general psychiatry, 69(11), 1169–1178. https://doi.org/10.1001/archgenpsychiatry.2012.50
11) Arnsten A. F. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature reviews. Neuroscience, 10(6), 410–422. https://doi.org/10.1038/nrn2648
12) Tang, Y. Y., Hölzel, B. K., & Posner, M. I. (2015). The neuroscience of mindfulness meditation. Nature reviews. Neuroscience, 16(4), 213–225. https://doi.org/10.1038/nrn3916
13) Abel, T., Havekes, R., Saletin, J. M., & Walker, M. P. (2013). Sleep, plasticity and memory from molecules to whole-brain networks. Current biology : CB, 23(17), R774–R788. https://doi.org/10.1016/j.cub.2013.07.025
14) Marelli, S., Castelnuovo, A., Somma, A., Castronovo, V., Mombelli, S., Bottoni, D., Leitner, C., Fossati, A., & Ferini-Strambi, L. (2021). Impact of COVID-19 lockdown on sleep quality in university students and administration staff. Journal of neurology, 268(1), 8–15. https://doi.org/10.1007/s00415-020-10056-6