Bestselling author, comedian and mental health campaigner, Ruby Wax, has told CNBC that politicians "better get ready" to address the levels of anxiety caused by the coronavirus crisis.
The performer, who was awarded an OBE by Queen Elizabeth II for her services to mental health in 2015, said that since the lockdown response to Covid-19, "we all wake up in the morning on a rollercoaster."
"We just weren't prepared for this kind of emergency. In a war, everybody knows to get in the tube or the subway because you know where the bombs are coming from. But now, where's the danger?' she asked.
"A little human only has so much bandwidth, you know, we still have these cave-man brains and don't realize the wallpaper's changed. And if we have too much fear and no rest, we get frazzled."
Wax argued that mental health issues can impact peoples' health more broadly and so politicians had to take it seriously.
"I think people have to address what's going to happen after this. I'm not a politician, I don't know what to say, but they better get ready," she added.
On Thursday, the United Nations released a policy brief on Covid-19 and mental health highlighting an urgent need for increased investment in services to avoid "a massive increase in mental health conditions in the coming months."
"It is now crystal clear that mental health needs must be treated as a core element of our response to and recovery from the Covid-19 pandemic," Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO), said in an accompanying news release.
"A failure to take people's emotional well-being seriously will lead to long-term social and economic costs to society."
A 2016 WHO-led study on scaling up the treatment of depression and anxiety estimated that such disorders cost the global economy $1 trillion each year in lost productivity.
In the U.S. alone, one in five people already experience mental illness each year according to NAMI, the National Alliance on Mental Illness, the country's largest grassroots mental health organization.
American-born Wax became famous on U.K. television as a comedian and comedy writer before qualifying with a Master's degree in Mindfulness-based Cognitive Therapy from Oxford University in 2013.
She has been very open about her own experience with depression and, in 2017, started her charity Frazzled Café, which offers peer-to-peer support for anyone "overwhelmed by the stresses of modern life." During the lockdown response to Covid-19, the café has moved online.
Wax told CNBC that she is seeing people who have had previous experience of mental illness being better prepared than most for coping with the response to the pandemic.
"People that are agoraphobics or people that, you know, have a long line of depression are the ones that are being the most resilient because they're used to having to go into the world and now the world is coming into them. They're used to this kind of rollercoaster," she said.
"The people that were quite successful and they have kids and they have very important jobs now, contained in a little space, they've never had anything that indicated they would fail, and the failure is what's terrifying."
Wax, who is the author of books including "Sane New World" and "A Mindfulness Guide for the Frazzled", finished writing her fifth book during lockdown.
"And Now for the Good News…To the Future with Love" is due for release in September and will look at alternative ways to do business, education, community, technology, food and health.
Meanwhile, the mental health activist told CNBC her tips to help alleviate anxiety.
"When people care about each other, and they really are focused now, the world changes. The world could have changed before if we were a little more connected," she said. "I think people spread compassion just like they do viruses."
She advised people try things like mindfulness to calm their stress hormones, Tai Chi, martial arts and, "I don't know, knitting, something, stroking your cat."
"It is about kindness. If you're sweet to yourself, then you will be to other people."