Last responders: Mental health damage from Covid could last a generation, professionals say

"I have never been as busy in my life and I've never seen my colleagues as busy," Valentine Raiteri, a psychiatrist working in New York, told CNBC.

"I can't refer people to other people because everybody is full. Nobody's taking new patients ... So I've never been as busy in my life, during the pandemic, and ever in my career," he said, adding that he's also seen an influx of former patients returning to him for help.

Raiteri said that many of his patients are still working remotely and were isolated, with many feeling "disconnected and lost, and they just have this kind of malaise."

"That is really hard for me to do anything about," he said, noting: "I can't make the pressures disappear. I can always treat the illness that it provokes."

Numerous studies on the impact of Covid on mental health have been carried out. One study, published in The Lancet medical journal in October, looked at the global prevalence of depression and anxiety disorders in 204 countries and territories in 2020 due to the Covid pandemic.

It found that mental health dramatically declined in that year, with an estimated 53 million additional cases of major depressive disorders and 76 million additional cases of anxiety disorders seen globally. Women and younger people were found to be affected more than men and older adults.

As the pandemic really took hold in the spring of 2020, there was little understanding of how long the pandemic would last. Psychologists say there was a surprising amount of resilience during the first few months of the virus' outbreak, particularly when many countries went into unprecedented lockdowns.

Raiteri said that over time, however, the loss of daily social contact started to take its toll.

"There's definitely a huge mental health impact from a long period of uncertainty and change that's left people very isolated and not sure how to connect. Just being out in public and interacting in a very casual way with strangers or mild acquaintances, that's very regulating, and norm-creating and reality affirming."

When we stop getting those signals, Raiteri said, "our internal voices become stronger and it becomes harder and harder to self regulate."

That created a "big pressure cooker, especially for people who already have a vulnerability," he said.

Natalie Bodart, a London-based clinical psychologist and head of The Bodart Practice, told CNBC that the pandemic meant that many people had to confront issues in their life that they'd been able to avoid before, such as alcoholism, relationship issues, isolation and loneliness.

"Our day to day lives serve as great defense mechanisms, we have lots of distractions that help us to avoid things, for good and for ill," she said.

"For example, we have had younger people that have come to us and said, 'now that I'm not doing my very sociable busy job anymore, I realize I've got a problem with alcohol.' And why is that? Well, that's because it can't be covered up anymore by the fact that their work demands that they socialize and drink a lot. Or, people who have been in relationships where they don't see that much of their partner, so it works, it functions, but then you're stuck at home with that person and suddenly realize, actually, there's a lot of things coming out that we just haven't confronted or haven't realized."

For some people, particularly those with acute social anxiety, Covid lockdowns provided the perfect cover, however.

"For many people, they work really hard, pushing themselves to interact more with other people to socialize more, and Covid just meant that they didn't have to do that anymore. So they were talking about this huge sense of relief," Leigh Jones, a clinical psychologist and the co-founder of Octopus Psychology, told CNBC.

"But although they were kind of delighted when it first happened, then [they were] being really worried about facing people again. And that's been a kind of across the board, people with social anxiety, people with personality disorder, who are avoidant of other people, because ... it wasn't so much the isolation that was difficult. It was the getting back out there," said Jones, who works with both public and private patients in Leeds and Bradford in northern England.

"For practically everybody I see, Covid has had some kind of impact," she said, noting she has other patients "who have huge issues around feeling very, very vulnerable to harm or illness" or contagion.

"Obviously, for them, this has been their worst nightmare," she said.

To date, there have been over 400 million Covid cases around the world and over 5.7 million deaths, according to data compiled by Johns Hopkins University. Restrictions on social contact have prevented millions of people from sharing not just milestones like births and weddings with family and friends, but also final moments with loved ones, with many unable to hold or attend funerals during the strictest points of lockdown.

Jones noted that she had concerns over the loss of "rituals" associated with death. "I do really worry about the impact on grieving, because we have rituals for a reason, which is to help us process the loss and the grief," she said.

Katherine Preedy, a clinical psychologist based near London, told CNBC that she is seeing "a lot of trauma, either people who've lost people due to Covid" or have experienced other traumatic situations such as not being able to visit sick or dying relatives because of restrictions.

"This is a whole generation [that's been affected by Covid], it's two years of our lives, I think this will have a big impact. There may be first responders, people in hospitals, who are still very much in that survival mode, and then, there's obviously the emotional impact on people, whole industries being lost, the health [impact]."

She noted that mental health professionals are also under pressure to help a greatly increased number of patients.

"We're a nation that's traumatized and under stress; the whole world is under trauma and stress, which means we, like the people we work with, have fewer resources to draw on and have to work a bit harder to make sure we're looking after ourselves," she continued.

Bereavement, isolation, uncertainty and loss — a loss of freedoms, relationships and moments that can't be relived and retrieved — are just some of the issues that have affected many people during the pandemic. Psychologists say that while the pandemic may be in its "endgame" phase now, the mental health impact of Covid could be felt for years.

Alex Desatnik, a consultant clinical psychologist in the U.K. working with adults and children, told CNBC that he believes it will take "at least a generation" to resolve the damage to many young people caused by missed milestones and experiences crucial for development.

"Kids who grew up in this state, in this condition, and those things that they were deprived of, they will take this with them through life. I hope that as a society we will do as much as we can to compensate for what happened, and is still happening, actually," he said.

"You are a 15-year-old teenager only once," he said. "Everything we know about brain development, physical development, emotional development, with each age there is a unique window of opportunities" in which to grow, learn and develop, he said.

Milestones linked to age and development are, once passed, tricky to go back and "repair" Desatnik noted.

The advent of Covid vaccines has heralded what we all hope is the beginning of the end of the pandemic, despite new variants like omicron posing challenges to the shots that have been developed. The threat of a new mutation that could pose a more severe risk to health is also a concern.

For now, however, most developed nations with widespread vaccination coverage, and booster programs, are reopening and getting back to normal, or a "new normal" — perhaps one in which routine mask-wearing and Covid testing are a part of our lives for the foreseeable future.

Bodart noted that "one thing we're maybe confronting now at this stage in the pandemic, in my opinion, is this sense that we're not really going back, we're not going back to how things were."

"We've kind of got into this very hybrid living situation now, where companies and most places ... seem to be accepting that this hybrid situation is going to be continuing. So there's a bit of a strange feeling about that — how does that feel? To know that life has, sort of, changed now? And maybe for many people of a particular generation, this is the first major life transition of that kind that's come about," she noted.

The pandemic had offered an opportunity for people to look within and to confront personal issues and problems, and has forced many to do so. There can even be positive outcomes to that, Bodart said.

"I think for some people, they have gone back to things that they needed ... things have opened up a bit and so that's been very helpful," she said.

"But maybe for other people, if they've been put in touch with something, they've become aware of something, then you can't really bury that again. That's going to be something that you then have to work through and address, and maybe that's a good thing."