Memory loss, fatigue and trouble concentrating can be symptoms of having had coronavirus.
But scientists think people who haven’t had Covid are also suffering increased tiredness, impaired decision-making and a lack of focus due to the pandemic.
Experts believe Covid uncertainty and disruption to routines have led to a phenomenon known as “pandemic brain”.
A leading behavioural neuroscientist is now calling for more research into it.
“People form habits so we see friends on a particular day or enjoy a sport on a particular evening – and that lack of regularity can be quite challenging,” said Dr Emma Yhnell.
Has the pandemic affected your brain?
“Uncertainty influences the biology of our brains – and generally we can cope with a certain amount of uncertainty but the longer we have it, generally the worse it is for our brain.
“Lots of research has looked at the effect of Covid infection on the brain but actually we know that living in a pandemic more generally really has had impacts on our brain function and brain health.”
The UK has a population of more than 68 million people and the latest government figures show there have been more than 18.9 million confirmed UK Covid cases since January 2020.
‘I was hesitant to hug my mum’
Sannan Iqbal said he was “hesitant” to hug his mum during the pandemic as the 22-year-old with cystic fibrosis shielded to protect himself.
He said he felt like he “had a tonne of bricks” on his shoulders with “nowhere to escape” as he tried to avoid getting Covid.
“This pandemic has taken its toll on me” said Sannan, who lives with his parents in Cardiff.
“I do feel more fatigued, I do feel more anxious, I do feel myself questioning or even triple questioning my decisions.”
Sannan, whose condition affects his mobility, remembers being “glued to the television” when Covid hit the UK, trying to understand the restrictions and statistics.
“I already have mental health issues because of my disability, so all this added stress and pressure didn’t help,” he told BBC Wales Live.
He said his care services were withdrawn during the first lockdown in March 2020, leaving his anxiety levels “sky high”, and affecting his relationship with his parents, who are both key workers.
‘What happens if my parents caught Covid?’
“I relied on those services to give me and my parents a bit of respite from each other,” he said.
“I was a bit hesitant to even hug my own mother at most points during the pandemic.
“What happens if one of my parents caught Covid or were asymptomatic and brought it home? Would I be safe? Would I be able to cope?”
Scientists think regular changes in lockdown rules, travel restrictions, worries about getting the virus and limited face-to-face contact with others has affected some people’s brain health.
For Abbie Wright, losing her job at an insurance company during the pandemic impacted her routine and affected her focus.
‘I feel like my memory is gone’
“The uncertainty, it was just awful. And you couldn’t see the end,” said the 27-year-old from Barry in Vale of Glamorgan.
“I feel like my memory is gone. Brain fog has been a definite big thing for me. Forgetting words to use in a sentence and forgetting a simple sum.”
Abbie was diagnosed with borderline personality disorder in October 2019, just months before the pandemic, and the uncertainty meant she stopped doing things that would normally help her.
“I love going to the cinema, I love going to concerts,” she said.
“That’s a big part of my life – just anything that takes my mind off things. Things that you take for granted and were normal pre-pandemic now just seem alien.
“Then it’s the anxiety of getting back out there now restrictions are lifting.”
More research needed into ‘pandemic brain’ impact
Now there are calls for more research into the psychological impact of living through a pandemic for those who didn’t get Covid.
“This term ‘pandemic brain’ has cropped up – and the really interesting thing about it is that different people will have different experiences,” said Dr Yhnell, a senior neuroscience lecturer at Cardiff University.
“We know people who have experienced chronic stress or chronic anxiety see some changes to their brain in the parts that are involved in decision making and attention.
“But we need much more research to determine whether the experience of the pandemic has caused structural changes in people’s brains.”
If you have been affected by any of the issues in this story, the BBC Action Line has links to organisations which can offer support and advice