Alice Mao

Burnout can make one feel helpless, incompetent, emotionally exhausted, isolated and cynical. Yale faculty provided insight into the neurobiological basis behind symptoms of burnout — and what can be done to reverse it.

Professor of neuroscience and psychology Amy Arnsten’s decades of research on the effects of stress on the brain were inspired by seeing “how people fall apart,” she said. When her father was very ill, Arnsten witnessed the process by which people who are normally “very rational” can suddenly become “emotional tornadoes.” Through volunteering in her local state psychiatric hospital, she further witnessed how even small stressors had immediate effects on thought patterns. Arnsten found that understanding the effects of stress on the brain would provide vital clues as to how higher brain functioning is regulated.

“A lot of my own research is on how uncontrollable stress affects the prefrontal cortex, which is the most recently evolved part of our brains,” Arnsten said. “It does higher cognition, abstract thought, working memory, the executive functions — so being able to concentrate, multitask, plan and organize, all these things you ideally need to thrive at Yale, for example.”

Arnsten highlighted that a person’s perceived ability to control a stressor is a key determinant of its effect on their brain. For example, if someone is overwhelmed by what is being asked of them, believing it to be beyond their capabilities even if it is not, they will view the task as something to be afraid of and such fear will prevail. The stress signaling pathways engaged will then weaken the prefrontal cortex and strengthen more primitive parts of the brain. According to Arnsten, this phenomenon may have had survival value over the course of human evolution. 

Arnsten recounted walking in the woods in Vermont, when suddenly along the path, a bear appeared in front of her. Luckily, the bear was facing the other way. Rather than consciously reasoning that most mammals lack a ventral stream, and therefore would not be able to recognize a still object, she froze. In this moment of fear, her reflex of freezing was engaged. When the bear turned around, it did not notice her because of her lack of movement, and ended up wandering off.

“Freezing is a reflex that can be mediated by the brainstem,” Arnsten explained. “So you can see that there are many instances where having this rapid switch to more primitive brain circuits can save your life. But there are others where the stressor really demands that you need your prefrontal cortex online. For example, during COVID, being able to imagine an invisible virus, you can’t see it the way you see a bear.”

Human neuroimaging can help researchers study the prefrontal cortex’s specific response to stress, such as the stress students experience before an important exam. Arnsten pointed to a Cornell study that analyzed the brains of medical students after a month of preparation for a major board exam. 

The month of study for the exam can be characterized as “psychosocial stress,” an imbalance between adverse life situations and one’s ability to cope with them. Brain imaging revealed that the stressor of studying for the major exam weakened the connectivity of the prefrontal network, leading to impaired prefrontal function and impaired attention regulation.

“We can see symptoms of breakdown when we begin to lose our ability to concentrate,” clinical assistant professor of psychiatry Mark Rego said. “We have the tip of the tongue phenomenon, we lose things easily — these are both from working memory breaking down — and our emotions escape their confines into harsh speech. Eventually the system will break down and we will need to rest to focus at all.”

The Cornell study found that after a month of reduced stress, these effects disappeared. In healthy individuals, the plasticity of the prefrontal cortex allowed for such cognitive impairments from stress to be reversed. However, this cycle could threaten long-term mental health.

In Rego’s book “Frontal Fatigue” he hypothesized that if this cycle of mentally breaking down and resting is repeated enough, the prefrontal cortex can become vulnerable to dysfunction, possibly leading to mental disorders. Rego terms this vulnerability “frontal fatigue,” defining it as a background condition caused by the “unique pressures of modern life” overwhelming the prefrontal cortex. 

Rego said that if frontal fatigue represents a state of vulnerability, then burnout is the next step before stress overwhelms an individual into a state of depression. Rego quoted Arnsten’s conclusion that if something is deemed “mental illness,” then it likely involves the prefrontal cortex.

“[The prefrontal cortex] does not function well under stress,” Rego said. “Virtually all imaging and injury studies have found that mental illness always involves the [prefrontal cortex].  Change the [prefrontal cortex] and changes in personality and behavior follow.”

According to Rego, without the prefrontal cortex, humans would be unable to control any action compelled by emotion. The prefrontal cortex’s numerous connections to the limbic system, where emotions form, explain its vital role in dealing with “our emotional lives,” he explained. 

Professor of psychology Laurie Santos said that burnout consists of three different phases. The first is emotional exhaustion, characterized by feeling worn out and drained, with not even a good night’s sleep seeming to help. The second phase is known as depersonalization or cynicism. This stage causes a person to be annoyed with others, have a shorter fuse, become more cynical of people’s intentions and become more distant with people.

“The final feature is a reduced sense of personal accomplishment,” Santos said. “You never feel like you’re doing things effectively and so you feel ineffective and like the work you do doesn’t matter. If you notice signs like this, it’s important that you pay attention early on and make some changes in order to feel better.”

Because it is the prefrontal cortex that helps control emotions and thereby avoid panicking, this continual stress cycle can cause a person to spiral downwards. Meanwhile, primitive circuits like the amygdala are strengthened, becoming enlarged as a result of burnout.

“The amygdala’s job is to look for threats,” Arnsten said. “And it’s something called the aversive lens, where people who are depressed, their amygdala actually views neutral faces as sad or threatening. So, yes, by being in chronic stress, you’re setting up your brain to be concentrating on the negative and interpreting things in a negative way.”

Arnsten advised people to have a low threshold for reaching out for help. She observed that many students may not be aware that help is available, and may view asking for help as a personal sign of weakness. She noted the importance of a balanced diet, deep breathing, exercise and good sleep.

Rego emphasized the need to lean into life “with your hands, senses and via others.” To allow the prefrontal cortex to rest, he suggested doing hands-on activities, such as arts and cooking, and indulging the senses — especially in nature — and talking to people often. Rego also recommended quieting the mind, whether through sports, long walks or yoga.

“Understanding the neuroscience can give you perspective to say ‘it’s not that I’m stupid or weak,’” Arnsten said. “This is how our neurobiology is built. This is a natural response of my brain, and I need to do things that will help me feel more in control.”

Students can schedule meetings with counselors at Yale Mental Health & Counseling by calling (203) 432-0290, or access the expanded mental health services through Yale College Community Counseling.

Kayla Yup covers Science & Social Justice and the Yale New Haven Health System for the SciTech desk. For the Arts desk, she covers anything from galleries to music. She is majoring in Molecular, Cellular & Developmental Biology and History of Science, Medicine & Public Health as a Global Health Scholar.