Nizzi, who has been working on a survey of Americans' mental health since April of last year, said the pandemic has caused many Americans to develop chronic stress, which could lead to them behaving more aggressively in their daily lives. "People can't have an emergency stress response that stays the same forever, so they convert from an acute stress response to a chronic stress response," she said. "As the stress becomes chronic, their ability to cope with all of the changes is starting to be overwhelmed."... Psychologists are worried about the ramifications, and some say there could be a connection between these mental health issues and behavioral changes that are starting to manifest across the country. There have been many reports of people behaving aggressively on airplanes over the past several months, for example, and Nizzi said this could be a result of people struggling with chronic stress and anxiety. There has also been a rise in anti-Asian hate crimes, domestic violence and more that could be partially, but not entirely, tied to poor mental health conditions in the U.S., she added.