The World Health Organization just declared the novel coronavirus a pandemic.
The massive stock market volatility of the last few weeks, including the worst week since the 2008 financial crisis, is another example.
A study from Oxford University published in the journal Nature Neuroscience helps explain what panic does to the human brain. Researchers found that when panic and anxiety are present, these stimuli create a glitch in the brain’s higher-order decision-making center. More simply said, anxiety and panic can cloud our judgment.
Individuals under high stress may struggle to gauge environmental cues that could help them avoid worse outcomes, according to the Oxford researchers.
Additionally, neuroscientists at the University of Pittsburgh have found that anxiety and panic disrupt neurons in the prefrontal cortex -- the area of the brain responsible for decision making -- and that can affect long-term planning, understanding rules, calculating the consequences of various risks and rewards, regulating emotions and problem solving.
"Panic leads your brain to think with emotion rather than intellectual higher processes of your brain," said Mona Degan, a primary care physician in Los Angeles. "This can lead to irrational decisions, especially if we are part of a large group of people trying to do the same thing, such as stocking up on household supplies, which leads to unnecessary shortages."
Panic prevention should be a crucial goal of emergency management, because panic is contagious and destructive.
Outbreaks from recent history have evoked similar responses, including Severe Acute Respiratory Syndrome (SARS) in 2002 and Middle East Respiratory Syndrome (MERS) in 2012.
So why does mass hysteria impede more appropriate responses to containment?
"Anxiety triggers our bodies to go into flight-or-fight mode, a natural human response to danger, which in turn secretes cortisol," a stress hormone, Degan explained. When activated, stress hormones can hinder a person's immune system.
Excess anxiety also can affect other hormones, including adrenaline, said Dr. Alexander Sanchez, a psychiatrist in New York City.
"This imbalance of hormones can lead to the areas [of the brain] responsible for making responsible decisions, like the prefrontal cortex, to lose function," Sanchez added. "People lose sense of proportion and start to imagine the worst possible scenario, even if it is unlikely."
It also can lead to xenophobia and discrimination, even though, as Degan reminded us, "This virus does not infect people based off race -- anyone is susceptible."
"It is important to keep calm and act logically in the face of a potential crisis. Take a moment to take a deep breath," Sanchez said. "Read the recommendations from a trustworthy news source, develop a rational plan and then try not to dwell on all the possibilities.
"What you should do instead is all of the things that we know help people to relax in general: Get good sleep, eat well and exercise if you are healthy enough."
Yalda Safai M.D., M.P.H., is a psychiatry resident in New York City and a contributor to the ABC News Medical Unit.